Apparatus and method for performing power control in wireless power transfer system

ABSTRACT

A wireless power transmitter includes a power conversion unit configured to transfer wireless power to a wireless power receiver by forming magnetic coupling with the wireless power receiver; and a communication/control unit configured to communicate with the wireless power receiver to control transmission of the wireless power and to perform transmission or reception of data, wherein the communication/control unit is configured to: receive, from the wireless power receiver after a configuration phase, a received power packet (RPP) which indicates a value of the wireless power received by the wireless power receiver; transmit, to the wireless power receiver, a bit pattern which requests communication initiated by the wireless power transmitter in response to the RPP when the communication/control unit has data to be sent to the wireless power receiver; and receive a packet for polling the data to be sent from the wireless power receiver in response to the bit pattern.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/488,195 filed on Aug. 22, 2019, which is the National Phase of PCTInternational Application No. PCT/KR2019/004582, filed on Apr. 16, 2019,which claims priority under 35 U.S.C. 119(a) to Patent Application No.10-2018-0043939, filed in Republic of Korea on Apr. 16, 2018 and PatentApplication No. 10-2018-0099226, filed in Republic of Korea on Aug. 24,2018, all of these applications are hereby expressly incorporated byreference into the present application.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to wireless power transfer, and moreparticularly, to an apparatus and method for performing power control ina wireless power transfer system.

Related Art

The wireless power transfer (or transmission) technology corresponds toa technology that can wirelessly transfer (or transmit) power between apower source and an electronic device. For example, by allowing thebattery of a wireless device, such as a smartphone or a tablet PC, andso on, to be recharged by simply loading the wireless device on awireless charging pad, the wireless power transfer technique may providemore outstanding mobility, convenience, and safety as compared to theconventional wired charging environment, which uses a wired chargingconnector. Apart from the wireless charging of wireless devices, thewireless power transfer technique is raising attention as a replacementfor the conventional wired power transfer environment in diverse fields,such as electric vehicles, Bluetooth earphones, 3D glasses, diversewearable devices, household (or home) electric appliances, furniture,underground facilities, buildings, medical equipment, robots, leisure,and so on.

The wireless power transfer (or transmission) method is also referred toas a contactless power transfer method, or a no point of contact powertransfer method, or a wireless charging method. A wireless powertransmission system may be configured of a wireless power transmittersupplying electric energy by using a wireless power transfer method, anda wireless power receiver receiving the electric energy being suppliedby the wireless power transmitter and supplying the receiving electricenergy to a receiver, such as a battery cell, and so on.

The wireless power transfer technique includes diverse methods, such asa method of transferring power by using magnetic coupling, a method oftransferring power by using radio frequency (RF), a method oftransferring power by using microwaves, and a method of transferringpower by using ultrasound (or ultrasonic waves). The method that isbased on magnetic coupling is categorized as a magnetic induction methodand a magnetic resonance method. The magnetic induction methodcorresponds to a method transmitting power by using electric currentsthat are induced to the coil of the receiver by a magnetic field, whichis generated from a coil battery cell of the transmitter, in accordancewith an electromagnetic coupling between a transmitting coil and areceiving coil. The magnetic resonance method is similar to the magneticinduction method in that is uses a magnetic field. However, the magneticresonance method is different from the magnetic induction method in thatenergy is transmitted due to a concentration of magnetic fields on botha transmitting end and a receiving end, which is caused by the generatedresonance.

Wireless power systems implemented to follow specific standardtechnology may solve a safety problem when being overheated due toforeign objects. However, non-authenticated products that do not receiveproduct authentication on technical standards or specifications havebeen distributed in the market, whereby users may be exposed at risk.Therefore, in a process before and after wireless charging, by enablinga wireless power transmitting device and a wireless power receivingdevice to perform mutual authentication on genuine products, it isnecessary to secure stability and reliability.

SUMMARY OF THE INVENTION

The present invention provides a device and method for performingauthentication in a wireless power transfer system.

In an aspect, there is provided a wireless power transmitter. Thewireless power transmitter includes a power conversion unit configuredto transfer wireless power to a wireless power receiver by formingmagnetic coupling with the wireless power receiver, and acommunication/control unit configured to communicate with the wirelesspower receiver to control transmission of the wireless power and toperform transmission or reception of data.

In an aspect, the communication/control unit is configured to: receive,from the wireless power receiver, a received power packet (RPP) whichindicates a value of the wireless power received by the wireless powerreceiver; transmit, to the wireless power receiver, a bit pattern whichrequests communication initiated by the wireless power transmitter inresponse to the RPP when the communication/control unit has data to besent to the wireless power receiver; and receive a packet for pollingthe data to be sent from the wireless power receiver in response to thebit pattern.

In another aspect, the data to be sent comprises power relatedinformation for increasing or decreasing a level of the wireless power.

In another aspect, the RPP indicates that the wireless power receiver isin Mode 0.

In another aspect, when the RPP indicates a mode other than Mode 4, thecommunication/control unit is configured to transmit the bit pattern.

In another aspect, the bit pattern and the polling packet are 8 bitsrespectively.

In another aspect, there is provided a power control method performed bya wireless power transmitter. The method includes transferring wirelesspower to a wireless power receiver by forming magnetic coupling with thewireless power receiver, and communicating with the wireless powerreceiver to control transmission of the wireless power and to performtransmission or reception of data.

In another aspect, the performing of the transmission or reception ofthe data comprises: receiving, from the wireless power receiver, areceived power packet (RPP) which indicates a value of the wirelesspower received by the wireless power receiver; transmitting, to thewireless power receiver, a bit pattern which requests communicationinitiated by the wireless power transmitter in response to the RPP whenthe wireless power transmitter has data to be sent to the wireless powerreceiver; and receiving a packet for polling the data to be sent fromthe wireless power receiver in response to the bit pattern.

In another aspect, the data to be sent comprises power relatedinformation for increasing or decreasing a level of the wireless power.

In another aspect, the RPP indicates that the wireless power receiver isin Mode 0.

In another aspect, when the RPP indicates a mode other than Mode 4, thecommunication/control unit transmits the bit pattern.

In another aspect, the bit pattern and the polling packet are 8 bitsrespectively.

In another aspect, there is provided a wireless power receiver. Thewireless power receiver includes a power pickup unit configured toreceive wireless power from a wireless power transmitter by formingmagnetic coupling with the wireless power transmitter, and acommunication/control unit configured to communicate with the wirelesspower transmitter to control transmission of the wireless power and toperform transmission or reception of data.

In another aspect, the communication/control unit is configured to:transmit, to the wireless power transmitter, a received power packet(RPP) which indicates a value of the wireless power received by thewireless power receiver; receive, from the wireless power transmitter, abit pattern which requests communication initiated by the wireless powertransmitter in response to the RPP when the wireless power transmitterhas data to be sent to the wireless power receiver; and transmit apacket for polling the data to be sent to the wireless power transmitterin response to the bit pattern.

In another aspect, the data to be sent comprises power relatedinformation for increasing or decreasing a level of the wireless power.

In another aspect, the RPP indicates that the wireless power receiver isin Mode 0.

In another aspect, when the RPP indicates a mode other than Mode 4, thecommunication/control unit is configured to transmit the bit pattern.

In another aspect, the bit pattern and the polling packet are 8 bitsrespectively.

In another aspect, there is provided a power control method performed bya wireless power receiver. The method includes receiving wireless powerfrom a wireless power transmitter by forming magnetic coupling with thewireless power transmitter, and communicating with the wireless powertransmitter to control transmission of the wireless power and to performtransmission or reception of data.

In another aspect, the performing of the transmission or reception ofthe data comprises: transmitting, to the wireless power transmitter, areceived power packet (RPP) which indicates a value of the wirelesspower received by the wireless power receiver; receiving, from thewireless power transmitter, a bit pattern which requests communicationinitiated by the wireless power transmitter in response to the RPP whenthe wireless power transmitter has data to be sent to the wireless powerreceiver; and transmitting a packet for polling the data to be sent tothe wireless power transmitter in response to the bit pattern.

In another aspect, the data to be sent comprises power relatedinformation for increasing or decreasing a level of the wireless power.

In another aspect, the RPP indicates that the wireless power receiver isin Mode 0.

In another aspect, when the RPP indicates a mode other than Mode 4, thecommunication/control unit is configured to transmit the bit pattern.

In another aspect, bit pattern and the polling packet are 8 bitsrespectively.

Effect of the Invention

Essential elements, for example, a format of a wireless chargingcertificate, indication information on authentication function support,timing between an authentication related procedure and a wirelesscharging phase, an authentication procedure and an authenticationmessage, and a protocol of a lower level supporting the authenticationprocedure, for mutual authentication between a wireless powertransmitting device and receiving device are clearly provided by thepresent invention and thus even during wireless charging of high power,stability and reliability can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present invention.

FIG. 2 is a block diagram of a wireless power system (10) according toanother exemplary embodiment of the present invention.

FIG. 3 shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transmission system.

FIG. 4 is a block diagram of a wireless power transmission systemaccording to another exemplary embodiment of the present invention.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

FIG. 6 shows a power control method according to an exemplary embodimentof the present invention.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present invention.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present invention.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present invention.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present invention.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present invention.

FIG. 12 is a block diagram illustrating a wireless charging certificateformat according to an embodiment.

FIG. 13A is a block diagram illustrating a wireless charging certificateformat according to another embodiment.

FIG. 13B is a block diagram illustrating a wireless charging certificateformat according to another embodiment.

FIG. 14 illustrates a capability packet structure of a wireless powertransmitting device according to an embodiment.

FIG. 15 illustrates a capability packet structure of a wireless powertransmitting device according to another embodiment.

FIG. 16 illustrates a configuration packet structure of a wireless powerreceiving device according to an embodiment.

FIG. 17 illustrates a configuration packet structure of a wireless powerreceiving device according to another embodiment.

FIG. 18 is a flowchart illustrating a sequence of transmitted andreceived packets when a wireless power receiving device performsauthentication (authentication of PTx by PRx) of a wireless powertransmitting device according to an embodiment.

FIG. 19 illustrates an example of a message structure of GET_DIGESTS.

FIG. 20 illustrates another example of a message structure ofGET_DIGESTS.

FIG. 21 illustrates a physical packet structure that transmits DIGESTSand a method of transmitting the physical packet structure.

FIG. 22 illustrates an example of a message structure ofGET_CERTIFICATE.

FIG. 23 illustrates an example of a physical packet structure thattransmits a certificate and a method of transmitting the physical packetstructure.

FIG. 24 illustrates an example of a physical packet structure thattransmits an authentication response message of a wireless powertransmitting device and a method of transmitting the physical packetstructure.

FIG. 25 illustrates an example of a CHALLENGE message structure.

FIG. 26 illustrates an example of a physical packet structure thattransmits CHALLENGE_AUTH and a method of transmitting the physicalpacket structure.

FIG. 27 is a flowchart illustrating a sequence of transmitted andreceived packets when a wireless power transmitting device performsauthentication (authentication of PRx by PTx) of a wireless powerreceiving device according to an embodiment.

FIG. 28 illustrates an example of a message structure of GET_DIGESTStransmitted by a wireless power transmitting device.

FIG. 29 illustrates an example of a GET_CERTIFICATE message structuretransmitted by a wireless power transmitting device.

FIG. 30 illustrates an example of a physical packet structure thattransmits a certificate of a wireless power receiving device and amethod of transmitting the physical packet structure.

FIG. 31 illustrates an example of a CHALLENGE message structuretransmitted by a wireless power transmitting device.

FIG. 32 illustrates an example of a physical packet structure thattransmits CHALLENGE_AUTH of a wireless power receiving device and amethod of transmitting the physical packet structure.

FIG. 33 illustrates an example of a physical packet structure thattransmits an authentication response message of a wireless powerreceiving device and a method of transmitting the physical packetstructure.

FIG. 34 illustrates another example of a physical packet structure thattransmits an authentication response message of a wireless powerreceiving device and a method of transmitting the physical packetstructure.

FIG. 35 is a flowchart illustrating a sequence of transmitted andreceived packets when a wireless power transmitting device performsauthentication (authentication of PRx by PTx) of a wireless powerreceiving device according to another embodiment.

FIG. 36 illustrates a structure of a packet in which a wireless powerreceiving device transmits to a wireless power transmitting devicein-band communication.

FIG. 37 illustrates a structure of a packet in which a wireless powertransmitting device transmits to a wireless power receiving devicein-band communication.

FIG. 38 illustrates a transmission and reception sequence of a packetbetween a wireless power receiving device and transmitting device from alower level viewpoint according to an embodiment.

FIG. 39 illustrates a transmission and reception sequence of a packetbetween a wireless power receiving device and transmitting device from alower level viewpoint according to another embodiment.

FIG. 40 illustrates a structure of an extended control error packetaccording to an embodiment.

FIG. 41 illustrates a structure of an end power transfer (EPT) packetaccording to an embodiment.

FIG. 42 illustrates a structure of an extended received power packetaccording to an embodiment.

FIG. 43 illustrates a transmission and reception sequence of a packetbetween the wireless power receiving device and transmitting device froma lower level viewpoint according to an embodiment.

FIG. 44 illustrates data transport according to an embodiment.

FIG. 45 illustrates data transport according to another embodiment.

FIG. 46 illustrates a structure of an ADT data packet (ADT_PRx datapacket) on a wireless power receiving device according to an embodiment.

FIG. 47 illustrates a structure of an ADT response packet (ADT_PRxresponse packet) of a wireless power receiving device according to anembodiment.

FIG. 48 illustrates a structure of an ADT control packet (ADT_PRxcontrol packet) of a wireless power receiving device according to anembodiment.

FIG. 49 illustrates a structure of an ADT data packet (ADT_PTx datapacket) of a wireless power transmitting device according to anembodiment.

FIG. 50 illustrates a structure of an ADT response packet (ADT_PTxresponse packet) of a wireless power transmitting device according to anembodiment.

FIG. 51 illustrates a structure of an ADT response/control packet(ADT_PTx response/control packet) of a wireless power transmittingdevice according to an embodiment.

FIG. 52 illustrates a structure of an ADT control packet (ADT_PTxcontrol packet) of a wireless power transmitting device according to anembodiment.

FIG. 53 is a diagram illustrating a state machine of ADT data packetwrite according to an embodiment.

FIG. 54 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and a wireless powerreceiving device upon exchanging an ADT data packet according to anembodiment.

FIG. 55 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and a wireless powerreceiving device upon exchanging an ADT data packet according to anotherembodiment.

FIG. 56 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and a wireless powerreceiving device upon exchanging an ADT data packet according to anotherembodiment.

FIG. 57 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to an embodiment.

FIG. 58 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 59 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 60 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 61 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 62 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to an embodiment.

FIG. 63 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to another embodiment.

FIG. 64 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to another embodiment.

FIG. 65 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to another embodiment.

FIG. 66 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to another embodiment.

FIG. 67 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and a wireless powerreceiving device upon exchanging an ADT data packet according to anembodiment.

FIG. 68 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and a wireless powerreceiving device upon exchanging an ADT data packet according to anotherembodiment.

FIG. 69 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to an embodiment.

FIG. 70 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 71 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 72 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 73 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment.

FIG. 74 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to an embodiment.

FIG. 75 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to another embodiment.

FIG. 76 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to another embodiment.

FIG. 77 illustrates an exchange sequence of an ADT data packet of anauthentication response message according to another embodiment.

FIG. 78 illustrates a structure of a GRP according to an embodiment.

FIG. 79 illustrates a transmission sequence on power managementinitiated by a wireless power transmitting device according to anembodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The term “wireless power”, which will hereinafter be used in thisspecification, will be used to refer to an arbitrary form of energy thatis related to an electric field, a magnetic field, and anelectromagnetic field, which is transferred (or transmitted) from awireless power transmitter to a wireless power receiver without usingany physical electromagnetic conductors. The wireless power may also bereferred to as a wireless power signal, and this may refer to anoscillating magnetic flux that is enclosed by a primary coil and asecondary coil. For example, power conversion for wirelessly chargingdevices including mobile phones, cordless phones, iPods, MP3 players,headsets, and so on, within the system will be described in thisspecification. Generally, the basic principle of the wireless powertransfer technique includes, for example, all of a method oftransferring power by using magnetic coupling, a method of transferringpower by using radio frequency (RF), a method of transferring power byusing microwaves, and a method of transferring power by using ultrasound(or ultrasonic waves).

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present invention.

Referring to FIG. 1, the wireless power system (10) include a wirelesspower transmitter (100) and a wireless power receiver (200).

The wireless power transmitter (100) is supplied with power from anexternal power source (S) and generates a magnetic field. The wirelesspower receiver (200) generates electric currents by using the generatedmagnetic field, thereby being capable of wirelessly receiving power.

Additionally, in the wireless power system (10), the wireless powertransmitter (100) and the wireless power receiver (200) may transceive(transmit and/or receive) diverse information that is required for thewireless power transfer. Herein, communication between the wirelesspower transmitter (100) and the wireless power receiver (200) may beperformed (or established) in accordance with any one of an in-bandcommunication, which uses a magnetic field that is used for the wirelesspower transfer (or transmission), and an out-band communication, whichuses a separate communication carrier.

Herein, the wireless power transmitter (100) may be provided as a fixedtype or a mobile (or portable) type. Examples of the fixed transmittertype may include an embedded type, which is embedded in in-door ceilingsor wall surfaces or embedded in furniture, such as tables, an implantedtype, which is installed in out-door parking lots, bus stops, subwaystations, and so on, or being installed in means of transportation, suchas vehicles or trains. The mobile (or portable) type wireless powertransmitter (100) may be implemented as a part of another device, suchas a mobile device having a portable size or weight or a cover of alaptop computer, and so on.

Additionally, the wireless power receiver (200) should be interpreted asa comprehensive concept including diverse home appliances and devicesthat are operated by being wirelessly supplied with power instead ofdiverse electronic devices being equipped with a battery and a powercable. Typical examples of the wireless power receiver (200) may includeportable terminals, cellular phones, smartphones, personal digitalassistants (PDAs), portable media players (PDPs), Wibro terminals,tablet PCs, phablet, laptop computers, digital cameras, navigationterminals, television, electronic vehicles (EVs), and so on.

In the wireless power system (10), one wireless power receiver (200) ora plurality of wireless power receivers may exist. Although it is shownin FIG. 1 that the wireless power transmitter (100) and the wirelesspower receiver (200) send and receive power to and from one another in aone-to-one correspondence (or relationship), as shown in FIG. 2, it isalso possible for one wireless power transmitter (100) to simultaneouslytransfer power to multiple wireless power receivers (200-1, 200-2, . . ., 200-M). Most particularly, in case the wireless power transfer (ortransmission) is performed by using a magnetic resonance method, onewireless power transmitter (100) may transfer power to multiple wirelesspower receivers (200-1, 200-2, . . . , 200-M) by using a synchronizedtransport (or transfer) method or a time-division transport (ortransfer) method.

Additionally, although it is shown in FIG. 1 that the wireless powertransmitter (100) directly transfers (or transmits) power to thewireless power receiver (200), the wireless power system (10) may alsobe equipped with a separate wireless power transceiver, such as a relayor repeater, for increasing a wireless power transport distance betweenthe wireless power transmitter (100) and the wireless power receiver(200). In this case, power is delivered to the wireless powertransceiver from the wireless power transmitter (100), and, then, thewireless power transceiver may transfer the received power to thewireless power receiver (200).

Hereinafter, the terms wireless power receiver, power receiver, andreceiver, which are mentioned in this specification, will refer to thewireless power receiver (200). Also, the terms wireless powertransmitter, power transmitter, and transmitter, which are mentioned inthis specification, will refer to the wireless power transmitter (100).

FIG. 3 shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transmission system.

As shown in FIG. 3, the electronic devices included in the wirelesspower transmission system are sorted in accordance with the amount oftransmitted power and the amount of received power. Referring to FIG. 3,wearable devices, such as smart watches, smart glasses, head mounteddisplays (HMDs), smart rings, and so on, and mobile electronic devices(or portable electronic devices), such as earphones, remote controllers,smartphones, PDAs, tablet PCs, and so on, may adopt a low-power(approximately 5 W or less or approximately 20 W or less) wirelesscharging method.

Small-sized/Mid-sized electronic devices, such as laptop computers,robot vacuum cleaners, TV receivers, audio devices, vacuum cleaners,monitors, and so on, may adopt a mid-power (approximately 50 W or lessor approximately 200 W or less) wireless charging method. Kitchenappliances, such as mixers, microwave ovens, electric rice cookers, andso on, and personal transportation devices (or other electric devices ormeans of transportation), such as powered wheelchairs, powered kickscooters, powered bicycles, electric cars, and so on may adopt ahigh-power (approximately 2 kW or less or approximately 22 kW or less)wireless charging method.

The electric devices or means of transportation, which are describedabove (or shown in FIG. 1) may each include a wireless power receiver,which will hereinafter be described in detail. Therefore, theabove-described electric devices or means of transportation may becharged (or re-charged) by wirelessly receiving power from a wirelesspower transmitter.

Hereinafter, although the present invention will be described based on amobile device adopting the wireless power charging method, this ismerely exemplary. And, therefore, it shall be understood that thewireless charging method according to the present invention may beapplied to diverse electronic devices.

A standard for the wireless power transfer (or transmission) includes awireless power consortium (WPC), an air fuel alliance (AFA), and a powermatters alliance (PMA).

The WPC standard defines a baseline power profile (BPP) and an extendedpower profile (EPP). The BPP is related to a wireless power transmitterand a wireless power receiver supporting a power transfer of 5 W, andthe EPP is related to a wireless power transmitter and a wireless powerreceiver supporting the transfer of a power range greater than 5 W andless than 30 W.

Diverse wireless power transmitters and wireless power receivers eachusing a different power level may be covered by each standard and may besorted by different power classes or categories.

For example, the WPC may categorize (or sort) the wireless powertransmitters and the wireless power receivers as PC-1, PC0, PC1, andPC2, and the WPC may provide a standard document (or specification) foreach power class (PC). The PC-1 standard relates to wireless powertransmitters and receivers providing a guaranteed power of less than 5W. The application of PC-1 includes wearable devices, such as smartwatches.

The PC0 standard relates to wireless power transmitters and receiversproviding a guaranteed power of 5 W. The PC0 standard includes an EPPhaving a guaranteed power ranges that extends to 30 W. Although in-band(IB) communication corresponds to a mandatory communication protocol ofPC0, out-of-band (OBB) communication that is used as an optional backupchannel may also be used for PC0. The wireless power receiver may beidentified by setting up an OOB flag, which indicates whether or not theOOB is supported, within a configuration packet. A wireless powertransmitter supporting the OOB may enter an OOB handover phase bytransmitting a bit-pattern for an OOB handover as a response to theconfiguration packet. The response to the configuration packet maycorrespond to an NAK, an ND, or an 8-bit pattern that is newly defined.The application of the PC0 includes smartphones.

The PC1 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 30 W to 150 W. OOB correspondsto a mandatory communication channel for PC1, and IB is used forinitialization and link establishment to OOB. The wireless powertransmitter may enter an OOB handover phase by transmitting abit-pattern for an OOB handover as a response to the configurationpacket. The application of the PC1 includes laptop computers or powertools.

The PC2 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 200 W to 2 kW, and itsapplication includes kitchen appliances.

As described above, the PCs may be differentiated in accordance with therespective power levels. And, information on whether or not thecompatibility between the same PCs is supported may be optional ormandatory. Herein, the compatibility between the same PCs indicates thatpower transmission/reception between the same PCs is possible. Forexample, in case a wireless power transmitter corresponding to PC x iscapable of performing charging of a wireless power receiver having thesame PC x, it may be understood that compatibility is maintained betweenthe same PCs. Similarly, compatibility between different PCs may also besupported. Herein, the compatibility between different PCs indicatesthat power transmission/reception between different PCs is alsopossible. For example, in case a wireless power transmittercorresponding to PC x is capable of performing charging of a wirelesspower receiver having PC y, it may be understood that compatibility ismaintained between the different PCs.

The support of compatibility between PCs corresponds to an extremelyimportant issue in the aspect of user experience and establishment ofinfrastructure. Herein, however, diverse problems, which will bedescribed below, exist in maintaining the compatibility between PCs.

In case of the compatibility between the same PCs, for example, in caseof a wireless power receiver using a lap-top charging method, whereinstable charging is possible only when power is continuously transferred,even if its respective wireless power transmitter has the same PC, itmay be difficult for the corresponding wireless power receiver to stablyreceive power from a wireless power transmitter of the power toolmethod, which transfers power non-continuously. Additionally, in case ofthe compatibility between different PCs, for example, in case a wirelesspower transmitter having a minimum guaranteed power of 200 W transferspower to a wireless power receiver having a maximum guaranteed power of5 W, the corresponding wireless power receiver may be damaged due to anovervoltage. As a result, it may be inappropriate (or difficult) to usethe PS as an index/reference standard representing/indicating thecompatibility.

Hereinafter, ‘profiles’ will be newly defined based on indexes/referencestandards representing/indicating the compatibility. More specifically,it may be understood that by maintaining compatibility between wirelesspower transmitters and receivers having the same ‘profile’, stable powertransmission/reception may be performed, and that powertransmission/reception between wireless power transmitters and receivershaving different ‘profiles’ cannot be performed. The ‘profiles’ may bedefined in accordance with whether or not compatibility is possibleand/or the application regardless of (or independent from) the powerclass.

For example, the profile may be sorted into 4 different categories, suchas i) Mobile, ii) Power tool, iii) Kitchen, and iv) Wearable.

In case of the ‘Mobile’ profile, the PC may be defined as PC0 and/orPC1, the communication protocol/method may be defined as IB and OOBcommunication, and the operation frequency may be defined as 87 to 205kHz, and smartphones, laptop computers, and so on, may exist as theexemplary application.

In case of the ‘Power tool’ profile, the PC may be defined as PC1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 145 kHz, and powertools, and so on, may exist as the exemplary application.

In case of the ‘Kitchen’ profile, the PC may be defined as PC2, thecommunication protocol/method may be defined as NFC-based communication,and the operation frequency may be defined as less than 100 kHz, andkitchen/home appliances, and so on, may exist as the exemplaryapplication.

In case of the ‘Wearable’ profile, the PC may be defined as PC-1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 205 kHz, and wearabledevices that are worn by the users, and so on, may exist as theexemplary application.

It may be mandatory to maintain compatibility between the same profiles,and it may be optional to maintain compatibility between differentprofiles.

The above-described profiles (Mobile profile, Power tool profile,Kitchen profile, and Wearable profile) may be generalized and expressedas first to nth profile, and a new profile may be added/replaced inaccordance with the WPC standard and the exemplary embodiment.

In case the profile is defined as described above, the wireless powertransmitter may optionally perform power transmission only to thewireless power receiving corresponding to the same profile as thewireless power transmitter, thereby being capable of performing a morestable power transmission. Additionally, since the load (or burden) ofthe wireless power transmitter may be reduced and power transmission isnot attempted to a wireless power receiver for which compatibility isnot possible, the risk of damage in the wireless power receiver may bereduced.

PC1 of the ‘Mobile’ profile may be defined by being derived from anoptional extension, such as OOB, based on PC0. And, the ‘Power tool’profile may be defined as a simply modified version of the PC1 ‘Mobile’profile. Additionally, up until now, although the profiles have beendefined for the purpose of maintaining compatibility between the sameprofiles, in the future, the technology may be evolved to a level ofmaintaining compatibility between different profiles. The wireless powertransmitter or the wireless power receiver may notify (or announce) itsprofile to its counterpart by using diverse methods.

In the AFA standard, the wireless power transmitter is referred to as apower transmitting unit (PTU), and the wireless power receiver isreferred to as a power receiving unit (PRU). And, the PTU is categorizedto multiple classes, as shown in Table 1, and the PRU is categorized tomultiple classes, as shown in Table 2.

TABLE 1 Minimum value for a maximum Minimum category number of P_(TX)_(—) _(IN) _(—) _(MAX) support requirement supported devices Class 1  2W 1x Category 1 1x Category 1 Class 2 10 W 1x Category 3 2x Category 2Class 3 16 W 1x Category 4 2x Category 3 Class 4 33 W 1x Category 5 3xCategory 3 Class 5 50 W 1x Category 6 4x Category 3 Class 6 70 W 1xCategory 7 5x Category 3

TABLE 2 PRU P_(RX) _(—) _(OUT) _(—) _(MAX′) Exemplary applicationCategory 1 TBD Bluetooth headset Category 2 3.5 W Feature phone Category3 6.5 W Smartphone Category 4 13 W Tablet PC, Phablet Category 5 25 WSmall form factor laptop Category 6 37.5 W General laptop Category 7 50W Home appliance

As shown in Table 1, a maximum output power capability of Class n PTUmay be equal to or greater than the PTX_IN_MAX of the correspondingclass. The PRU cannot draw a power that is higher than the power levelspecified in the corresponding category.

FIG. 4 is a block diagram of a wireless power transmission systemaccording to another exemplary embodiment of the present invention.

Referring to FIG. 4, the wireless power transmission system (10)includes a mobile device (450), which wirelessly receives power, and abase station (400), which wirelessly transmits power.

As a device providing induction power or resonance power, the basestation (400) may include at least one of a wireless power transmitter(100) and a system unit (405). The wireless power transmitter (100) maytransmit induction power or resonance power and may control thetransmission. The wireless power transmitter (100) may include a powerconversion unit (110) converting electric energy to a power signal bygenerating a magnetic field through a primary coil (or primary coils),and a communications & control unit (120) controlling the communicationand power transfer between the wireless power receiver (200) in order totransfer power at an appropriate (or suitable) level. The system unit(405) may perform input power provisioning, controlling of multiplewireless power transmitters, and other operation controls of the basestation (400), such as user interface control.

The primary coil may generate an electromagnetic field by using analternating current power (or voltage or current). The primary coil issupplied with an alternating current power (or voltage or current) of aspecific frequency, which is being outputted from the power conversionunit (110). And, accordingly, the primary coil may generate a magneticfield of the specific frequency. The magnetic field may be generated ina non-radial shape or a radial shape. And, the wireless power receiver(200) receives the generated magnetic field and then generates anelectric current. In other words, the primary coil wirelessly transmitspower.

In the magnetic induction method, a primary coil and a secondary coilmay have randomly appropriate shapes. For example, the primary coil andthe secondary coil may correspond to copper wire being wound around ahigh-permeability formation, such as ferrite or a non-crystalline metal.The primary coil may also be referred to as a primary core, a primarywinding, a primary loop antenna, and so on. Meanwhile, the secondarycoil may also be referred to as a secondary core, a secondary winding, asecondary loop antenna, a pickup antenna, and so on.

In case of using the magnetic resonance method, the primary coil and thesecondary coil may each be provided in the form of a primary resonanceantenna and a secondary resonance antenna. The resonance antenna mayhave a resonance structure including a coil and a capacitor. At thispoint, the resonance frequency of the resonance antenna may bedetermined by the inductance of the coil and a capacitance of thecapacitor. Herein, the coil may be formed to have a loop shape. And, acore may be placed inside the loop. The core may include a physicalcore, such as a ferrite core, or an air core.

The energy transmission (or transfer) between the primary resonanceantenna and the second resonance antenna may be performed by a resonancephenomenon occurring in the magnetic field. When a near fieldcorresponding to a resonance frequency occurs in a resonance antenna,and in case another resonance antenna exists near the correspondingresonance antenna, the resonance phenomenon refers to a highly efficientenergy transfer occurring between the two resonance antennas that arecoupled with one another. When a magnetic field corresponding to theresonance frequency is generated between the primary resonance antennaand the secondary resonance antenna, the primary resonance antenna andthe secondary resonance antenna resonate with one another. And,accordingly, in a general case, the magnetic field is focused toward thesecond resonance antenna at a higher efficiency as compared to a casewhere the magnetic field that is generated from the primary antenna isradiated to a free space. And, therefore, energy may be transferred tothe second resonance antenna from the first resonance antenna at a highefficiency. The magnetic induction method may be implemented similarlyto the magnetic resonance method. However, in this case, the frequencyof the magnetic field is not required to be a resonance frequency.Nevertheless, in the magnetic induction method, the loops configuringthe primary coil and the secondary coil are required to match oneanother, and the distance between the loops should be very close-ranged.

Although it is not shown in the drawing, the wireless power transmitter(100) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (120) may transmit and/or receiveinformation to and from the wireless power receiver (200). Thecommunications & control unit (120) may include at least one of an IBcommunication module and an OOB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (120) mayperform in-band (TB) communication by loading information in themagnetic wave and by transmitting the information through the primarycoil or by receiving a magnetic wave carrying information through theprimary coil. At this point, the communications & control unit (120) mayload information in the magnetic wave or may interpret the informationthat is carried by the magnetic wave by using a modulation scheme, suchas binary phase shift keying (BPSK) or amplitude shift keying (ASK), andso on, or a coding scheme, such as Manchester coding ornon-return-to-zero level (NZR-L) coding, and so on. By using theabove-described IB communication, the communications & control unit(120) may transmit and/or receive information to distances of up toseveral meters at a data transmission rate of several kbps.

The OOB communication module may also perform out-of-band communicationthrough a communication antenna. For example, the communications &control unit (120) may be provided to a near field communication module.Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (120) may control the overalloperations of the wireless power transmitter (100). The communications &control unit (120) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power transmitter (100).

The communications & control unit (120) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (120) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (120) may beprovided as a program that operates the communications & control unit(120).

By controlling the operation point, the communications & control unit(120) may control the transmitted power. The operation point that isbeing controlled may correspond to a combination of a frequency (orphase), a duty cycle, a duty ratio, and a voltage amplitude. Thecommunications & control unit (120) may control the transmitted power byadjusting any one of the frequency (or phase), the duty cycle, the dutyratio, and the voltage amplitude. Additionally, the wireless powertransmitter (100) may supply a consistent level of power, and thewireless power receiver (200) may control the level of received power bycontrolling the resonance frequency.

The mobile device (450) includes a wireless power receiver (200)receiving wireless power through a secondary coil, and a load (455)receiving and storing the power that is received by the wireless powerreceiver (200) and supplying the received power to the device.

The wireless power receiver (200) may include a power pick-up unit (210)and a communications & control unit (220). The power pick-up unit (210)may receive wireless power through the secondary coil and may convertthe received wireless power to electric energy. The power pick-up unit(210) rectifies the alternating current (AC) signal, which is receivedthrough the secondary coil, and converts the rectified signal to adirect current (DC) signal. The communications & control unit (220) maycontrol the transmission and reception of the wireless power (transferand reception of power).

The secondary coil may receive wireless power that is being transmittedfrom the wireless power transmitter (100). The secondary coil mayreceive power by using the magnetic field that is generated in theprimary coil. Herein, in case the specific frequency corresponds aresonance frequency, magnetic resonance may occur between the primarycoil and the secondary coil, thereby allowing power to be transferredwith greater efficiency.

Although it is not shown in FIG. 4, the communications & control unit(220) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control unit (220) may transmit and/or receiveinformation to and from the wireless power transmitter (100). Thecommunications & control unit (220) may include at least one of an IBcommunication module and an OOB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control unit (220) mayperform IB communication by loading information in the magnetic wave andby transmitting the information through the secondary coil or byreceiving a magnetic wave carrying information through the secondarycoil. At this point, the communications & control unit (120) may loadinformation in the magnetic wave or may interpret the information thatis carried by the magnetic wave by using a modulation scheme, such asbinary phase shift keying (BPSK) or amplitude shift keying (ASK), and soon, or a coding scheme, such as Manchester coding or non-return-to-zerolevel (NZR-L) coding, and so on. By using the above-described IBcommunication, the communications & control unit (220) may transmitand/or receive information to distances of up to several meters at adata transmission rate of several kbps.

The OOB communication module may also perform out-of-band communicationthrough a communication antenna. For example, the communications &control unit (220) may be provided to a near field communication module.

Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control unit (220) may control the overalloperations of the wireless power receiver (200). The communications &control unit (220) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power receiver (200).

The communications & control unit (220) may be implemented in a computeror a similar device as hardware, software, or a combination of the same.When implemented in the form of hardware, the communications & controlunit (220) may be provided as an electronic circuit performing controlfunctions by processing electrical signals. And, when implemented in theform of software, the communications & control unit (220) may beprovided as a program that operates the communications & control unit(220).

The load (455) may correspond to a battery. The battery may store energyby using the power that is being outputted from the power pick-up unit(210). Meanwhile, the battery is not mandatorily required to be includedin the mobile device (450). For example, the battery may be provided asa detachable external feature. As another example, the wireless powerreceiver may include an operating means that can execute diversefunctions of the electronic device instead of the battery.

As shown in the drawing, although the mobile device (450) is illustratedto be included in the wireless power receiver (200) and the base station(400) is illustrated to be included in the wireless power transmitter(100), in a broader meaning, the wireless power receiver (200) may beidentified (or regarded) as the mobile device (450), and the wirelesspower transmitter (100) may be identified (or regarded) as the basestation (400).

Hereinafter, the coil or coil unit includes a coil and at least onedevice being approximate to the coil, and the coil or coil unit may alsobe referred to as a coil assembly, a coil cell, or a cell.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

Referring to FIG. 5, the power transmission (or transfer) from thewireless power transmitter to the wireless power receiver according toan exemplary embodiment of the present invention may be broadly dividedinto a selection phase (510), a ping phase (520), an identification andconfiguration phase (530), a negotiation phase (540), a calibrationphase (550), a power transfer phase (560), and a renegotiation phase(570).

If a specific error or a specific event is detected when the powertransfer is initiated or while maintaining the power transfer, theselection phase (510) may include a shifting phase (or step)-referencenumerals S502, S504, S508, S510, and S512. Herein, the specific error orspecific event will be specified in the following description.Additionally, during the selection phase (510), the wireless powertransmitter may monitor whether or not an object exists on an interfacesurface. If the wireless power transmitter detects that an object isplaced on the interface surface, the process step may be shifted to theping phase (520). During the selection phase (510), the wireless powertransmitter may transmit an analog ping having an extremely short pulseand may detect whether or not an object exists within an active area ofthe interface surface based on a current change in the transmitting coilor the primary coil.

In case an object is sensed (or detected) in the selection phase (510),the wireless power transmitter may measure a quality factor of awireless power resonance circuit (e.g., power transmission coil and/orresonance capacitor). According to the exemplary embodiment of thepresent invention, during the selection phase (510), the wireless powertransmitter may measure the quality factor in order to determine whetheror not a foreign object exists in the charging area along with thewireless power receiver. In the coil that is provided in the wirelesspower transmitter, inductance and/or components of the series resistancemay be reduced due to a change in the environment, and, due to suchdecrease, a value of the quality factor may also be decreased. In orderto determine the presence or absence of a foreign object by using themeasured quality factor value, the wireless power transmitter mayreceive from the wireless power receiver a reference quality factorvalue, which is measured in advance in a state where no foreign objectis placed within the charging area. The wireless power transmitter maydetermine the presence or absence of a foreign object by comparing themeasured quality factor value with the reference quality factor value,which is received during the negotiation phase (540). However, in caseof a wireless power receiver having a low reference quality factorvalue—e.g., depending upon its type, purpose, characteristics, and soon, the wireless power receiver may have a low reference quality factorvalue-in case a foreign object exists, since the difference between thereference quality factor value and the measured quality factor value issmall (or insignificant), a problem may occur in that the presence ofthe foreign object cannot be easily determined. Accordingly, in thiscase, other determination factors should be further considered, or thepresent or absence of a foreign object should be determined by usinganother method.

According to another exemplary embodiment of the present invention, incase an object is sensed (or detected) in the selection phase (510), inorder to determine whether or not a foreign object exists in thecharging area along with the wireless power receiver, the wireless powertransmitter may measure the quality factor value within a specificfrequency area (e.g., operation frequency area). In the coil that isprovided in the wireless power transmitter, inductance and/or componentsof the series resistance may be reduced due to a change in theenvironment, and, due to such decrease, the resonance frequency of thecoil of the wireless power transmitter may be changed (or shifted). Morespecifically, a quality factor peak frequency that corresponds to afrequency in which a maximum quality factor value is measured within theoperation frequency band may be moved (or shifted).

In the ping phase (520), if the wireless power transmitter detects thepresence of an object, the transmitter activates (or Wakes up) areceiver and transmits a digital ping for identifying whether or not thedetected object corresponds to the wireless power receiver. During theping phase (520), if the wireless power transmitter fails to receive aresponse signal for the digital ping—e.g., a signal intensitypacket-from the receiver, the process may be shifted back to theselection phase (510). Additionally, in the ping phase (520), if thewireless power transmitter receives a signal indicating the completionof the power transfer—e.g., charging complete packet-from the receiver,the process may be shifted back to the selection phase (510).

If the ping phase (520) is completed, the wireless power transmitter mayshift to the identification and configuration phase (530) foridentifying the receiver and for collecting configuration and statusinformation.

In the identification and configuration phase (530), if the wirelesspower transmitter receives an unwanted packet (i.e., unexpected packet),or if the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., out of time), or if a packettransmission error occurs (i.e., transmission error), or if a powertransfer contract is not configured (i.e., no power transfer contract),the wireless power transmitter may shift to the selection phase (510).

The wireless power transmitter may confirm (or verify) whether or notits entry to the negotiation phase (540) is needed based on aNegotiation field value of the configuration packet, which is receivedduring the identification and configuration phase (530). Based on theverified result, in case a negotiation is needed, the wireless powertransmitter enters the negotiation phase (540) and may then perform apredetermined FOD detection procedure. Conversely, in case a negotiationis not needed, the wireless power transmitter may immediately enter thepower transfer phase (560).

In the negotiation phase (540), the wireless power transmitter mayreceive a Foreign Object Detection (FOD) status packet that includes areference quality factor value. Or, the wireless power transmitter mayreceive an FOD status packet that includes a reference peak frequencyvalue. Alternatively, the wireless power transmitter may receive astatus packet that includes a reference quality factor value and areference peak frequency value. At this point, the wireless powertransmitter may determine a quality coefficient threshold value for FOdetection based on the reference quality factor value. The wirelesspower transmitter may determine a peak frequency threshold value for FOdetection based on the reference peak frequency value.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined quality coefficientthreshold value for FO detection and the currently measured qualityfactor value (i.e., the quality factor value that was measured beforethe ping phase), and, then, the wireless power transmitter may controlthe transmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present invention will not be limited only to this.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined peak frequency thresholdvalue for FO detection and the currently measured peak frequency value(i.e., the peak frequency value that was measured before the pingphase), and, then, the wireless power transmitter may control thetransmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present invention will not be limited only to this.

In case the FO is detected, the wireless power transmitter may return tothe selection phase (510). Conversely, in case the FO is not detected,the wireless power transmitter may proceed to the calibration phase(550) and may, then, enter the power transfer phase (560). Morespecifically, in case the FO is not detected, the wireless powertransmitter may determine the intensity of the received power that isreceived by the receiving end during the calibration phase (550) and maymeasure power loss in the receiving end and the transmitting end inorder to determine the intensity of the power that is transmitted fromthe transmitting end. In other words, during the calibration phase(550), the wireless power transmitter may estimate the power loss basedon a difference between the transmitted power of the transmitting endand the received power of the receiving end. The wireless powertransmitter according to the exemplary embodiment of the presentinvention may calibrate the threshold value for the FOD detection byapplying the estimated power loss.

In the power transfer phase (560), in case the wireless powertransmitter receives an unwanted packet (i.e., unexpected packet), or incase the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., time-out), or in case a violation ofa predetermined power transfer contract occurs (i.e., power transfercontract violation), or in case charging is completed, the wirelesspower transmitter may shift to the selection phase (510).

Additionally, in the power transfer phase (560), in case the wirelesspower transmitter is required to reconfigure the power transfer contractin accordance with a status change in the wireless power transmitter,the wireless power transmitter may shift to the renegotiation phase(570). At this point, if the renegotiation is successfully completed,the wireless power transmitter may return to the power transfer phase(560).

The above-described power transfer contract may be configured based onthe status and characteristic information of the wireless powertransmitter and receiver. For example, the wireless power transmitterstatus information may include information on a maximum amount oftransmittable power, information on a maximum number of receivers thatcan be accommodated, and so on. And, the receiver status information mayinclude information on the required power, and so on.

FIG. 6 shows a power control method according to an exemplary embodimentof the present invention.

As shown in FIG. 6, in the power transfer phase (560), by alternatingthe power transmission and/or reception and communication, the wirelesspower transmitter (100) and the wireless power receiver (200) maycontrol the amount (or size) of the power that is being transferred. Thewireless power transmitter and the wireless power receiver operate at aspecific control point. The control point indicates a combination of thevoltage and the electric current that are provided from the output ofthe wireless power receiver, when the power transfer is performed.

More specifically, the wireless power receiver selects a desired controlpoint, a desired output current/voltage, a temperature at a specificlocation of the mobile device, and so on, and additionally determines anactual control point at which the receiver is currently operating. Thewireless power receiver calculates a control error value by using thedesired control point and the actual control point, and, then, thewireless power receiver may transmit the calculated control error valueto the wireless power transmitter as a control error packet.

Also, the wireless power transmitter may configure/control a newoperation point-amplitude, frequency, and duty cycle-by using thereceived control error packet, so as to control the power transfer.Therefore, the control error packet may be transmitted/received at aconstant time interval during the power transfer phase, and, accordingto the exemplary embodiment, in case the wireless power receiverattempts to reduce the electric current of the wireless powertransmitter, the wireless power receiver may transmit the control errorpacket by setting the control error value to a negative number. And, incase the wireless power receiver intends to increase the electriccurrent of the wireless power transmitter, the wireless power receivertransmit the control error packet by setting the control error value toa positive number. During the induction mode, by transmitting thecontrol error packet to the wireless power transmitter as describedabove, the wireless power receiver may control the power transfer.

In the resonance mode, which will hereinafter be described in detail,the device may be operated by using a method that is different from theinduction mode. In the resonance mode, one wireless power transmittershould be capable of serving a plurality of wireless power receivers atthe same time. However, in case of controlling the power transfer justas in the induction mode, since the power that is being transferred iscontrolled by a communication that is established with one wirelesspower receiver, it may be difficult to control the power transfer ofadditional wireless power receivers. Therefore, in the resonance modeaccording to the present invention, a method of controlling the amountof power that is being received by having the wireless power transmittercommonly transfer (or transmit) the basic power and by having thewireless power receiver control its own resonance frequency.Nevertheless, even during the operation of the resonance mode, themethod described above in FIG. 6 will not be completely excluded. And,additional control of the transmitted power may be performed by usingthe method of FIG. 6.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present invention. This may belongto a wireless power transmission system that is being operated in themagnetic resonance mode or the shared mode. The shared mode may refer toa mode performing a several-for-one (or one-to-many) communication andcharging between the wireless power transmitter and the wireless powerreceiver. The shared mode may be implemented as a magnetic inductionmethod or a resonance method.

Referring to FIG. 7, the wireless power transmitter (700) may include atleast one of a cover (720) covering a coil assembly, a power adapter(730) supplying power to the power transmitter (740), a powertransmitter (740) transmitting wireless power, and a user interface(750) providing information related to power transfer processing andother related information. Most particularly, the user interface (750)may be optionally included or may be included as another user interface(750) of the wireless power transmitter (700).

The power transmitter (740) may include at least one of a coil assembly(760), an impedance matching circuit (770), an inverter (780), acommunication unit (790), and a control unit (710).

The coil assembly (760) includes at least one primary coil generating amagnetic field. And, the coil assembly (760) may also be referred to asa coil cell.

The impedance matching circuit (770) may provide impedance matchingbetween the inverter and the primary coil(s). The impedance matchingcircuit (770) may generate resonance from a suitable frequency thatboosts the electric current of the primary coil(s). In a multi-coilpower transmitter (740), the impedance matching circuit may additionallyinclude a multiplex that routes signals from the inverter to a subset ofthe primary coils. The impedance matching circuit may also be referredto as a tank circuit.

The impedance matching circuit (770) may include a capacitor, aninductor, and a switching device that switches the connection betweenthe capacitor and the inductor. The impedance matching may be performedby detecting a reflective wave of the wireless power that is beingtransferred (or transmitted) through the coil assembly (760) and byswitching the switching device based on the detected reflective wave,thereby adjusting the connection status of the capacitor or the inductoror adjusting the capacitance of the capacitor or adjusting theinductance of the inductor. In some cases, the impedance matching may becarried out even though the impedance matching circuit (770) is omitted.This specification also includes an exemplary embodiment of the wirelesspower transmitter (700), wherein the impedance matching circuit (770) isomitted.

The inverter (780) may convert a DC input to an AC signal. The inverter(780) may be operated as a half-bridge inverter or a full-bridgeinverter in order to generate a pulse wave and a duty cycle of anadjustable frequency. Additionally, the inverter may include a pluralityof stages in order to adjust input voltage levels.

The communication unit (790) may perform communication with the powerreceiver. The power receiver performs load modulation in order tocommunicate requests and information corresponding to the powertransmitter. Therefore, the power transmitter (740) may use thecommunication unit (790) so as to monitor the amplitude and/or phase ofthe electric current and/or voltage of the primary coil in order todemodulate the data being transmitted from the power receiver.

Additionally, the power transmitter (740) may control the output powerto that the data can be transferred through the communication unit (790)by using a Frequency Shift Keying (FSK) method, and so on.

The control unit (710) may control communication and power transfer (ordelivery) of the power transmitter (740). The control unit (710) maycontrol the power transfer by adjusting the above-described operationpoint. The operation point may be determined by, for example, at leastany one of the operation frequency, the duty cycle, and the inputvoltage.

The communication unit (790) and the control unit (710) may each beprovided as a separate unit/device/chipset or may be collectivelyprovided as one unit/device/chipset.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present invention. This may belong to a wireless powertransmission system that is being operated in the magnetic resonancemode or the shared mode.

Referring to FIG. 8, the wireless power receiver (800) may include atleast one of a user interface (820) providing information related topower transfer processing and other related information, a powerreceiver (830) receiving wireless power, a load circuit (840), and abase (850) supporting and covering the coil assembly. Most particularly,the user interface (820) may be optionally included or may be includedas another user interface (820) of the wireless power receiver (800).

The power receiver (830) may include at least one of a power converter(860), an impedance matching circuit (870), a coil assembly (880), acommunication unit (890), and a control unit (810).

The power converter (860) may convert the AC power that is received fromthe secondary coil to a voltage and electric current that are suitablefor the load circuit. According to an exemplary embodiment, the powerconverter (860) may include a rectifier. The rectifier may rectify thereceived wireless power and may convert the power from an alternatingcurrent (AC) to a direct current (DC). The rectifier may convert thealternating current to the direct current by using a diode or atransistor, and, then, the rectifier may smooth the converted current byusing the capacitor and resistance. Herein, a full-wave rectifier, ahalf-wave rectifier, a voltage multiplier, and so on, that areimplemented as a bridge circuit may be used as the rectifier.Additionally, the power converter may adapt a reflected impedance of thepower receiver.

The impedance matching circuit (870) may provide impedance matchingbetween a combination of the power converter (860) and the load circuit(840) and the secondary coil. According to an exemplary embodiment, theimpedance matching circuit may generate a resonance of approximately 100kHz, which can reinforce the power transfer. The impedance matchingcircuit (870) may include a capacitor, an inductor, and a switchingdevice that switches the combination of the capacitor and the inductor.The impedance matching may be performed by controlling the switchingdevice of the circuit that configured the impedance matching circuit(870) based on the voltage value, electric current value, power value,frequency value, and so on, of the wireless power that is beingreceived. In some cases, the impedance matching may be carried out eventhough the impedance matching circuit (870) is omitted. Thisspecification also includes an exemplary embodiment of the wirelesspower receiver (200), wherein the impedance matching circuit (870) isomitted.

The coil assembly (880) includes at least one secondary coil, and,optionally, the coil assembly (880) may further include an elementshielding the metallic part of the receiver from the magnetic field.

The communication unit (890) may perform load modulation in order tocommunicate requests and other information to the power transmitter.

For this, the power receiver (830) may perform switching of theresistance or capacitor so as to change the reflected impedance.

The control unit (810) may control the received power. For this, thecontrol unit (810) may determine/calculate a difference between anactual operation point and a desired operation point of the powerreceiver (830). Thereafter, by performing a request for adjusting thereflected impedance of the power transmitter and/or for adjusting anoperation point of the power transmitter, the difference between theactual operation point and the desired operation point may beadjusted/reduced. In case of minimizing this difference, an optimalpower reception may be performed.

The communication unit (890) and the control unit (810) may each beprovided as a separate device/chipset or may be collectively provided asone device/chipset.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present invention. This may correspond to acommunication frame structure in a shared mode.

Referring to FIG. 9, in the shared mode, different forms of frames maybe used along with one another. For example, in the shared mode, aslotted frame having a plurality of slots, as shown in (A), and a freeformat frame that does not have a specified format, as shown in (B), maybe used. More specifically, the slotted frame corresponds to a frame fortransmitting short data packets from the wireless power receiver (200)to the wireless power transmitter (100). And, since the free formatframe is not configured of a plurality of slots, the free format framemay correspond to a frame that is capable of performing transmission oflong data packets.

Meanwhile, the slotted frame and the free format frame may be referredto other diverse terms by anyone skilled in the art. For example, theslotted frame may be alternatively referred to as a channel frame, andthe free format frame may be alternatively referred to as a messageframe.

More specifically, the slotted frame may include a sync patternindicating the starting point (or beginning) of a slot, a measurementslot, nine slots, and additional sync patterns each having the same timeinterval that precedes each of the nine slots.

Herein, the additional sync pattern corresponds to a sync pattern thatis different from the sync pattern that indicates the starting point ofthe above-described frame. More specifically, the additional syncpattern does not indicate the starting point of the frame but mayindicate information related to the neighboring (or adjacent) slots(i.e., two consecutive slots positioned on both sides of the syncpattern).

Among the nine slots, each sync pattern may be positioned between twoconsecutive slots. In this case, the sync pattern may provideinformation related to the two consecutive slots.

Additionally, the nine slots and the sync patterns being provided beforeeach of the nine slots may have the same time interval. For example, thenine slots may have a time interval of 50 ms. And, the nine syncpatterns may have a time length of 50 ms.

Meanwhile, the free format frame, as shown in (B) may not have aspecific format apart from the sync pattern indicating the startingpoint of the frame and the measurement slot. More specifically, the freeformat frame is configured to perform a function that is different fromthat of the slotted frame. For example, the free format frame may beused to perform a function of performing communication of long datapackets (e.g., additional owner information packets) between thewireless power transmitter and the wireless power receiver, or, in caseof a wireless power transmitter being configured of multiple coils, toperform a function of selecting any one of the coils.

Hereinafter, a sync pattern that is included in each frame will bedescribed in more detail with reference to the accompanying drawings.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present invention.

Referring to FIG. 10, the sync pattern may be configured of a preamble,a start bit, a response field, a type field, an info field, and a paritybit. In FIG. 10, the start bit is illustrated as ZERO.

More specifically, the preamble is configured of consecutive bits, andall of the bits may be set to 0. In other words, the preamble maycorrespond to bits for matching a time length of the sync pattern.

The number of bits configuring the preamble may be subordinate to theoperation frequency so that the length of the sync pattern can be mostapproximate to 50 ms but within a range that does not exceed 50 ms. Forexample, in case the operation frequency corresponds to 100 kHz, thesync pattern may be configured of two preamble bits, and, in case theoperation frequency corresponds to 105 kHz, the sync pattern may beconfigured of three preamble bits.

The start bit may correspond to a bit that follows the preamble, and thestart bit may indicate ZERO. The ZERO may correspond to a bit thatindicates a type of the sync pattern. Herein, the type of sync patternsmay include a frame sync including information that is related to aframe, and a slot sync including information of the slot. Morespecifically, the sync pattern may be positioned between consecutiveframes and may correspond to a frame sync that indicate a start of theframe, or the sync pattern may be positioned between consecutive slotsamong a plurality of slots configuring the frame and may correspond to async slot including information related to the consecutive slots.

For example, in case the ZERO is equal to 0, this may indicate that thecorresponding slot is a slot sync that is positioned in-between slots.And, in case the ZERO is equal to 1, this may indicate that thecorresponding sync pattern is a frame sync being located in-betweenframes.

A parity bit corresponds to a last bit of the sync pattern, and theparity bit may indicate information on a number of bits configuring thedata fields (i.e., the response field, the type field, and the infofield) that are included in the sync pattern. For example, in case thenumber of bits configuring the data fields of the sync patterncorresponds to an even number, the parity bit may be set to when, and,otherwise (i.e., in case the number of bits corresponds to an oddnumber), the parity bit may be set to 0.

The response field may include response information of the wirelesspower transmitter for its communication with the wireless power receiverwithin a slot prior to the sync pattern. For example, in case acommunication between the wireless power transmitter and the wirelesspower receiver is not detected, the response field may have a value of‘00’. Additionally, if a communication error is detected in thecommunication between the wireless power transmitter and the wirelesspower receiver, the response field may have a value of ‘01’. Thecommunication error corresponds to a case where two or more wirelesspower receivers attempt to access one slot, thereby causing collision tooccur between the two or more wireless power receivers.

Additionally, the response field may include information indicatingwhether or not the data packet has been accurately received from thewireless power receiver. More specifically, in case the wireless powertransmitter has denied the data packet, the response field may have avalue of “10” (10—not acknowledge (NAK)). And, in case the wirelesspower transmitter has confirmed the data packet, the response field mayhave a value of “11” (11—acknowledge (ACK)).

The type field may indicate the type of the sync pattern. Morespecifically, in case the sync pattern corresponds to a first syncpattern of the frame (i.e., as the first sync pattern, in case the syncpattern is positioned before the measurement slot), the type field mayhave a value of ‘1’, which indicates a frame sync.

Additionally, in a slotted frame, in case the sync pattern does notcorrespond to the first sync pattern of the frame, the type field mayhave a value of ‘0’, which indicates a slot sync.

Moreover, the information field may determine the meaning of its valuein accordance with the sync pattern type, which is indicated in the typefield. For example, in case the type field is equal to 1 (i.e., in casethe sync pattern type indicates a frame sync), the meaning of theinformation field may indicate the frame type. More specifically, theinformation field may indicate whether the current frame corresponds toa slotted frame or a free-format frame. For example, in case theinformation field is given a value of ‘00’, this indicates that thecurrent frame corresponds to a slotted frame. And, in case theinformation field is given a value of ‘01’, this indicates that thecurrent frame corresponds to a free-format frame.

Conversely, in case the type field is equal to 0 (i.e., in case the syncpattern type indicates a slot sync), the information field may indicatea state of a next slot, which is positioned after the sync pattern. Morespecifically, in case the next slot corresponds to a slot that isallocated (or assigned) to a specific wireless power receiver, theinformation field is given a value of ‘00’. In case the next slotcorresponds to a slot that is locked, so as to be temporarily used bythe specific wireless power receiver, the information field is given avalue of ‘01’. Alternatively, in case the next slot corresponds to aslot that can be freely used by a random wireless power receiver, theinformation field is given a value of ‘10’.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present invention.

Referring to FIG. 11, the wireless power receiver operating in theshared mode may be operated in any one of a selection phase (1100), anintroduction phase (1110), a configuration phase (1120), a negotiationphase (1130), and a power transfer phase (1140).

Firstly, the wireless power transmitter according to the exemplaryembodiment of the present invention may transmit a wireless power signalin order to detect the wireless power receiver. More specifically, aprocess of detecting a wireless power receiver by using the wirelesspower signal may be referred to as an Analog ping.

Meanwhile, the wireless power receiver that has received the wirelesspower signal may enter the selection phase (1100). As described above,the wireless power receiver that has entered the selection phase (1100)may detect the presence or absence of an FSK signal within the wirelesspower signal.

In other words, the wireless power receiver may perform communication byusing any one of an exclusive mode and a shared mode in accordance withthe presence or absence of the FSK signal.

More specifically, in case the FSK signal is included in the wirelesspower signal, the wireless power receiver may operate in the sharedmode, and, otherwise, the wireless power receiver may operate in theexclusive mode.

In case the wireless power receiver operates in the shared mode, thewireless power receiver may enter the introduction phase (1110). In theintroduction phase (1110), the wireless power receiver may transmit acontrol information (CI) packet to the wireless power transmitter inorder to transmit the control information packet during theconfiguration phase, the negotiation phase, and the power transferphase. The control information packet may have a header and informationrelated to control. For example, in the control information packet, theheader may correspond to 0X53.

In the introduction phase (1110), the wireless power receiver performsan attempt to request a free slot for transmitting the controlinformation (CI) packet during the following configuration phase,negotiation phase, and power transfer phase. At this point, the wirelesspower receiver selects a free slot and transmits an initial CI packet.If the wireless power transmitter transmits an ACK as a response to thecorresponding CI packet, the wireless power transmitter enters theconfiguration phase. If the wireless power transmitter transmits a NACKas a response to the corresponding CI packet, this indicates thatanother wireless power receiver is performing communication through theconfiguration and negotiation phase. In this case, the wireless powerreceiver re-attempts to perform a request for a free slot.

If the wireless power receiver receives an ACK as a response to the CIpacket, the wireless power receiver may determine the position of aprivate slot within the frame by counting the remaining sync slots up tothe initial frame sync. In all of the subsequent slot-based frames, thewireless power receiver transmits the CI packet through thecorresponding slot.

If the wireless power transmitter authorizes the entry of the wirelesspower receiver to the configuration phase, the wireless powertransmitter provides a locked slot series for the exclusive usage of thewireless power receiver. This may ensure the wireless power receiver toproceed to the configuration phase without any collision.

The wireless power receiver transmits sequences of data packets, such astwo identification data packets (IDHI and IDLO), by using the lockedslots. When this phase is completed, the wireless power receiver entersthe negotiation phase. During the negotiation state, the wireless powertransmitter continues to provide the locked slots for the exclusiveusage of the wireless power receiver. This may ensure the wireless powerreceiver to proceed to the negotiation phase without any collision.

The wireless power receiver transmits one or more negotiation datapackets by using the corresponding locked slot, and the transmittednegotiation data packet(s) may be mixed with the private data packets.Eventually, the corresponding sequence is ended (or completed) alongwith a specific request (SRQ) packet. When the corresponding sequence iscompleted, the wireless power receiver enters the power transfer phase,and the wireless power transmitter stops the provision of the lockedslots.

In the power transfer phase, the wireless power receiver performs thetransmission of a CI packet by using the allocated slots and thenreceives the power. The wireless power receiver may include a regulatorcircuit. The regulator circuit may be included in acommunication/control unit. The wireless power receiver mayself-regulate a reflected impedance of the wireless power receiverthrough the regulator circuit. In other words, the wireless powerreceiver may adjust the impedance that is being reflected for an amountof power that is requested by an external load. This may prevent anexcessive reception of power and overheating.

In the shared mode, (depending upon the operation mode) since thewireless power transmitter may not perform the adjustment of power as aresponse to the received CI packet, in this case, control may be neededin order to prevent an overvoltage state.

Hereinafter, authentication between a wireless power transmitting deviceand a wireless power receiving device will be described. When thewireless power transmitting device and the wireless power receivingdevice are implemented by the same predefined power transfer interfaceand communication interface, the wireless power transmitting device andthe wireless power receiving device may be compatible, and powertransfer may be performed normally. Even if the wireless powertransmitting device and receiving device are not made by the samemanufacturer, when the wireless power transmitting device and receivingdevice are produced by the same technical standard or specification, thewireless power transmitting device and receiving device may becompatible with each other. However, even if the wireless powertransmitting device and receiving device follow the same technicalstandard, each manufacturer has a different implementation quality, andwhen manufacturers do not follow faithfully and accurately the standard,wireless charging of the wireless power transmitting device andreceiving device is not smoothly performed. In particular, in a producthaving a problem in foreign object detection (FOD) and overheatingprotection function, there is a risk of a safety accident such asexplosion. Therefore, a standardization organization operating technicalstandards provides a service that tests whether a wireless powertransmitting device or a wireless power receiving device of eachmanufacturer accurately complies standard technology and whether deviceinteroperability is kept and a genuine product authentication servicethrough an authorized authentication organization.

Nevertheless, because it is actually difficult to fundamentally blockthat non-authorized products are circulated in the market, in a processbefore and after wireless charging, by performing mutual authenticationon whether wireless power transmitting devices and wireless powerreceiving devices already circulated in the market are genuine products,it is necessary to ensure stability and reliability. That is, when it isa pre-authentication procedure that an authorized authenticationorganization grants genuine product authentication before productlaunch, but it may be referred to as a post-authentication procedure toperform an authentication procedure between products in an operation ofwireless charging after product launch. For example, mutualauthentication between products may be performed through an in-bandcommunication channel and may be compatible with USB-C authentication.When authentication is failed, the wireless power receiving device maywarn a user to perform charging in a low power mode or remove a powersignal.

In the present specification, Qi standard of WPC as standard technologyis exemplified, but the technical scope of the present inventionincludes an embodiment of authentication based on other standards aswell as Qi standard.

When introducing USB-C authentication in a wireless power transfersystem using in-band communication, a capability index of the followingtable is derived. That is, USB-C may be a model for wireless chargingauthentication.

TABLE 3 Type of authenti- Authentication of Authentication of cation PTxby PRx PRx by PTx Full 176,607.5 msec (~2.9 min) 26,922.5 msec (~27 sec)authenti- cation Quick 18,564.5 msec (~18 sec) 5,842.5 msec (~6 sec)authenti- cation

In Table 3, PRx means a wireless power receiving device, and PTx means awireless power transmitting device. Authentication includesauthentication of the wireless power transmitting device by the wirelesspower receiving device and authentication of the wireless powerreceiving device by the wireless power transmitting device.

When authenticating the wireless power transmitting device using fullauthentication, a long time of maximum about 3 minutes may be consumed,and this is because a large size of a USB-C certificate and acommunication protocol of a low bit rate in which the wireless powertransfer system employs. In particular, a situation in which such fullauthentication occurs every time in a public venue in which the userfrequently changes a wireless charging spot may give inconvenience tothe user. Therefore, it is necessary to compactly or simply define asize of a chain or a packet related to authentication. It is preferableto maintain a security level (ECDSA with SHA256) of 128 bits in USB-Cauthentication while maintaining a full authentication time to areasonable time (within 60 seconds). A time required for authenticationmay be increased because of repeated transmission of data due to atraffic error.

Hereinafter, specific embodiments of a certificate, an authenticationprocedure, an authentication message, and a communication protocol of alower level that executes an authentication procedure used forauthentication of standard technology will be disclosed. Communication,protocols, messages, and packets related to all authentication describedhereinafter may be generated, handled, stored, transmitted, andprocessed by communication and control units 220 and 120 andcommunication units 790 and 890 described in the present specification.

1. Wireless Charging Certificate

In terms of a chain level of the certificate, a level of a certificatechain may be limited. For example, the level of the certificate chainmay be 3. Even when a minimum chain level is operated, manufacturers mayissue certificates for products thereof, and a burden of themanufacturers and a certificate authority (CA) may also be reduced. Thecertificate chain is a series of two or more certificates, and eachcertificate is signed by a preceding certificate in the chain.

In terms of a certificate type, it may be defined that two types ofcertificates are transmitted between the wireless power transmittingdevice and receiving device. Here, two types of certificates may includean intermediate certificate and a leaf certificate. A root certificateis the same to both that support mutual authentication. The rootcertificate is a first certificate in the certificate chain and isself-signed. The leaf certificate is a final certificate in thecertificate chain, and the intermediate certificate is neither a rootcertificate nor a leaf certificate in the certificate chain.

In terms of the certificate format, the format of the certificate may bedefined to a reduced or simplified format. Here, the “reduced” or“simplified” format may mean a reduced or simplified format for wirelesscharging, compared with a certificate format (X509v3 format) of USB-C.For example, the simplified certificate format for the intermediatecertificate and the leaf certificate may be smaller than 100 bytes(e.g., 80 bytes). In this case, the root certificate may still follow acertificate format of USB-C. Hereinafter, the simplified certificateformat may be referred to as a wireless charging certificate format or aQi certificate format. Because a wireless power transfer system thatsupports out-of-band (OOB) communication, as in PC1 may use a widerbandwidth, a wireless charging certificate according to a USB-C formatmay be provided.

FIG. 12 is a block diagram illustrating a wireless charging certificateformat according to an embodiment.

Referring to FIG. 12, the wireless charging certificate format includesa certificate type, a certificate length, identification information(ID), a reserved bit (reserved), a public key, and a signature.

The certificate type is configured with, for example, 1 byte, mayrepresent that the corresponding certificate is any one of a rootcertificate/intermediate certificate/leaf certificate, represent thatthe certificate is a certificate of the wireless power transmittingdevice or a certificate of the wireless power receiving device, andrepresent all of two information. For example, when bit strings b0 to b3of the certificate type are ‘0000’b, it may represent that thecertificate is an intermediate certificate, and when bit strings b0 tob3 of the certificate type are ‘0001’b, it may represent that thecertificate is a leaf certificate. When bit strings b7 to b4 of thecertificate type are ‘0001’b, it may represent that the certificate is acertificate of the wireless power transmitting device, and when bitstrings b7 to b4 of the certificate type are ‘0000’b, it may representthat the certificate is a certificate of the wireless power receivingdevice. Therefore, when the bit string of the certificate type becomes aparticular value, the corresponding certificate is a certificate of thewireless power transmitting device and may be a leaf certificate.

The certificate length is configured with, for example, 2 bytes and maybe indicated in a byte unit.

The ID is configured with, for example, 6 bytes and may indicate amanufacturer code of the wireless power transmitting device or amanufacturer code of the wireless power receiving device or mayrepresent wireless power ID (WPID).

The reserved may be configured with, for example, 7 bytes. The publickey may be configured with, for example, 32 bytes. The signature may beconfigured with, for example, 32 bytes or 64 bytes.

When authentication is performed with in-band communication based on thewireless charging certificate format of FIG. 12, mutual fullauthentication may be completed within a minute, as shown in Table 4.

TABLE 4 Type of authenti- Authentication of Authentication of cation PTxby PRx PRx by PTx Full 34,830 msec (~35 sec) 8,002.5 msec (~8 sec)authenti- cation Quick 18,564.5 msec (~18 sec) 5,842.5 msec (~6 sec)authenti- cation

FIG. 12 exemplifies a case where a size of the certificate format is 80bytes, but this is merely an illustration and embodiments in which eachfield is defined to different bit numbers are apparent to those skilledin the art and correspond to the technical scope of the presentinvention.

FIG. 13A is a block diagram illustrating a wireless charging certificateformat according to another embodiment.

Referring to FIG. 13A, the wireless charging certificate format includesa certificate type, PTx and leaf indicator (PTx and leaf), a certificatelength, identification information (ID), a reserved, a public key, and asignature.

In the wireless charging certificate format of FIG. 13A, PTx and leafare separated from the certificate type to be allocated to a bitdifferent from that of the certificate type within the same byte B0.

The certificate type is configured with, for example, 6 bits, mayrepresent that the corresponding certificate is any one of a rootcertificate/intermediate certificate/leaf certificate, represent acertificate of the wireless power transmitting device or a certificateof the wireless power receiving device, and represent all of twoinformation.

The PTx and leaf indicate whether the corresponding certificate is acertificate of the wireless power transmitting device and is a leafcertificate. That is, the PTx and leaf may indicate whether thecorresponding certificate is a leaf certificate of the wireless powertransmitting device.

The PTx and leaf may be configured with, for example, 2 bits and may beconfigured in a form including a PTx indicator of 1 bit and a leafindicator of 1 bit. In this case, the PTx indicator indicates 1 when thecorresponding certificate is a certificate of the wireless powertransmitting device and indicates 0 when the corresponding certificateis a certificate of the wireless power receiving device. Further, theleaf indicator is configured with 1 bit, and when the correspondingcertificate is a leaf certificate, a value thereof may be set to 1 andwhen the corresponding certificate is not a leaf certificate, a valuethereof may be set to 0. FIG. 13A represents that the correspondingcertificate is a PTx leaf certificate because each bit is set to 1.

The PTx and leaf are included within the same byte B0 as that of thecertificate type, are configured in a right next bit string of thecertificate type, and are allocated to a bit different from that of thecertificate type.

The certificate length is configured with, for example, 1 byte and mayindicate a length of the corresponding certificate in a byte unit.

The identification information is configured with, for example, 6 bytesand may indicate a manufacturer code of the wireless power transmittingdevice or a PRx manufacturer code (PRMC) of the wireless power receivingdevice or may represent wireless power ID (WPID). Alternatively, whenthe certificate type is an intermediate certificate, identificationinformation may represent a manufacturer code of the wireless powertransmitting device or a manufacturer code of the wireless powerreceiving device, and when the certificate type is a leaf certificate,identification information may represent WPID.

The reserved may be configured with, for example, 4 bytes. The publickey may be configured with, for example, 32 bytes. The signature may beconfigured with, for example, 64 bytes.

When authentication is performed with in-band communication based on thewireless charging certificate format of FIG. 13A, mutual fullauthentication may be completed within 60 seconds, as shown in Table 5.

TABLE 5 Type of authenti- Authentication Authentication cation of PTx byPRx of PRx by PTx Full 39,782.5 msec (~40 sec) 8,761.5 msec (~9 sec)authenti- cation Quick 18,564.5 msec (~18 sec) 5,842.5 msec (~6 sec)authenti- cation

FIG. 13A exemplifies a case where a size of the certificate format is108 bytes, but this is merely an illustration and embodiments in whicheach field is defined to different bit numbers are apparent to thoseskilled in the art and correspond to the technical scope of the presentinvention.

As commercial capability requirements, it is preferable that in theauthentication procedure, authentication by an initiator of a responderin an environment using in-band communication is completed within 60seconds. Further, in the authentication procedure, it is preferable toprovide a mechanism for secure recognition of a previously authenticatedresponder within 20 seconds in an environment using in-bandcommunication.

FIG. 13B is a block diagram illustrating a wireless charging certificateformat according to another embodiment.

Referring to FIG. 13B, the wireless charging certificate format includesa wireless charging standard certificate structure version (QiAuthentication Certificate Structure Version), a reserved bit(reserved), a PTx and leaf indicator (PTx leaf), a certificate type, asignature offset, a serial number, issuer ID, subject ID, a public key,and a signature.

In the wireless charging certificate format, the PTx and leaf indicatoris separated from the certificate type to be allocated to a bitdifferent from that of a certificate type within the same byte B0.

The PTx leaf indicates whether the corresponding certificate is acertificate of the wireless power transmitting device and is a leafcertificate. That is, the PTx leaf may indicate whether thecorresponding certificate is a leaf certificate of the wireless powertransmitting device.

The PTx leaf may be configured with 1 bit unlike that of FIG. 13A. Ifthe PTx leaf is 0, it may indicate that the corresponding certificate isnot a leaf certificate or is a leaf certificate of the wireless powerreceiving device. If the PTx leaf is 1, it may indicate that thecorresponding certificate is a leaf certificate of the wireless powertransmitting device.

The certificate type may be configured with, for example, 2 bits and mayrepresent that the corresponding certificate is any one of a rootcertificates/intermediate certificate/leaf certificate and may representall of a root certificates/intermediate certificate/leaf certificate.

2. Indication Information on Authentication Function Support

When any one of the wireless power transmitting device and the wirelesspower receiving device does not support an authentication function(e.g., already launched legacy products may not support a newauthentication function), an authentication procedure therebetweencannot be performed. That is, in order to perform an authenticationprocedure, both the wireless power transmitting device and the wirelesspower receiving device need to support an authentication function.However, because an authentication function may be supported or may notbe supported according to a version of the product and according to themanufacturer, a procedure of determining support of the authenticationfunction and a message to be used for the procedure are required.Further, when only one device of the wireless power transmitting deviceand receiving device supports an authentication function and when theother device is a legacy product, backward compatibility for a minimumcharge function should be satisfied. A device that does not supportauthentication according to a system policy should support 5 W (orminimum power of 5 W or less, i.e. 3 W).

The wireless power transmitting device may notify the wireless powerreceiving device using a capability packet whether an authenticationfunction is supported (authentication of the wireless power transmittingdevice by the wireless power receiving device (authentication of PTx byPRx)). The wireless power receiving device may notify the wireless powertransmitting device using a configuration packet whether anauthentication function is supported (authentication of the wirelesspower receiving device by the wireless power transmitting device(authentication of PRx by PTx)). Hereinafter, a structure of indicationinformation (capability packet and configuration packet) on whether anauthentication function is supported will be described in detail.

FIG. 14 illustrates a capability packet structure of a wireless powertransmitting device according to an embodiment.

Referring to FIG. 14, a capability packet in which a correspondingheader value is 0X31 is configured with 3 bytes, and a first byte B0thereof includes a power class and a guaranteed power value, a secondbyte B1 thereof includes reserved and a potential power value, and athird byte B2 thereof includes reserved, Auth, NFCPP, NFCD, WPID, andNot Res Sens. Specifically, the Auth is configured with 1 bit and forexample, when a value thereof is 0, it indicates that the wireless powertransmitting device does not support an authentication function, andwhen a value thereof is 1, it indicates that the wireless powertransmitting device supports an authentication function.

FIG. 15 illustrates a capability packet structure of a wireless powertransmitting device according to another embodiment.

Referring to FIG. 15, a capability packet in which a correspondingheader value is 0X31 is configured with 3 bytes, and a first byte B0thereof includes a power class and a guaranteed power value, a secondbyte B1 thereof includes reserved and a potential power value, and athird byte B2 thereof includes an authentication initiator (AI), anauthentication responder (AR), reserved, WPID, and Not Res Sens.Specifically, the AI is configured with 1 bit and for example, when avalue thereof is ‘1b’, it indicates that the corresponding wirelesspower transmitting device operates as an authentication initiator.Further, the AR is configured with 1 bit and for example, when a valuethereof is ‘1b’, it indicates that the corresponding wireless powertransmitting device operates as an AR.

FIG. 16 illustrates a configuration packet structure of the wirelesspower receiving device according to an embodiment.

Referring to FIG. 16, a configuration packet in which a correspondingheader value is 0X51 is configured with 5 bytes, a first byte B0 thereofincludes a power class and a maximum power value, a second byte B1thereof includes reserved, a third byte B2 thereof includes Prop,reserved, ZERO, and Count, a fourth byte B3 thereof includes a windowsize and a window offset, and a fifth byte B4 thereof includes Neg,polarity, depth, Auth, and reserved. Specifically, the Auth isconfigured with 1 bit, and for example, when a value thereof is 0, itindicates that the corresponding power receiving device does not supportan authentication function, and when a value thereof is 1, it indicatesthat the wireless power receiving device supports an authenticationfunction.

FIG. 17 illustrates a configuration packet structure of a wireless powerreceiving device according to another embodiment.

Referring to FIG. 17, a configuration packet in which a correspondingheader value is 0X51 is configured with 5 bytes, a first byte B0 thereofincludes a power class and a maximum power value, a second byte B1thereof includes AI, AR, and reserved, a third byte B2 thereof includesProp, reserved, ZERO, and Count, a fourth byte B3 thereof includes awindow size and a window offset, and a fifth byte B4 thereof includesNeg, polarity, depth, Auth, and reserved. Specifically, the AI isconfigured with 1 bit, and for example, when a value thereof is ‘1b’, itindicates that the corresponding power receiving device operates as anAI. Further, the AR is configured with 1 bit, and for example, when avalue thereof is ‘1b’, it indicates that the wireless power receivingdevice operates as an AR.

3. Timing Between Authentication Related Procedures and WirelessCharging Phase

A procedure of determining whether the authentication function supportand an authentication procedure may be performed over at least one or aplurality of phases of identification and configuration phases, anegotiation phase, a calibration phase, a power transfer phase, arenegotiation phase, and an introduction phase.

As an example, the authentication procedure may be performed in thenegotiation phase. However, when quick authentication is performed inthe negotiation phase, a process of reading and determining DIGESTS within-band communication may take about 4 seconds. Therefore, in terms ofuser convenience, it may be considered to provide wireless charging withbasic power even before authentication regardless of authenticationrather than to start charging after authentication is complete. This ispreferable in terms of backward compatibility for devices having noauthentication function.

As another example, the authentication procedure may be performed over anegotiation phase and a power transfer phase. During the identificationand configuration phase, a packet sequence is strictly controlled, andonly one-way communication from the wireless power receiving device tothe wireless power transmitting device is allowed, but duringnegotiation and power transfer phases, two-way communication is allowed.Therefore, in negotiation and power transfer phases in which two-waycommunication is allowed, an authentication procedure may be performed.In the negotiation phase, quick authentication is performed by thewireless power transmitting device or receiving device that exchanges{GET_DIGESTS, CHALLENGE} message. A power contract may be signed basedon established trust. When the wireless power transmitting device andreceiving device first meet by checking DIGESTS, in order to establishan initial power contract based on a system policy and to providedefault low power to the wireless power receiving device as soon aspossible, the wireless power transmitting device and receiving deviceenter the power transfer phase. During the power transfer phase, fullauthentication is performed by the wireless power transmitting device orreceiving device that exchanges {GET_CERTIFICATE, CHALLENGE} message.When full authentication is completed successfully, the wireless powertransmitting device and/or receiving device renew(s) a power contract.

As another example, the wireless power transmitting device and receivingdevice may perform an authentication procedure in the power transferphase just after entering to the power transfer phase withoutauthentication. When authentication is successful in the power transferphase, the power contract may be renewed through the renegotiation phaseor the wireless power transmitting device may support supportable targetpower or full power to a level in which the wireless power transmittingdevice/receiving device wants. Therefore, user convenience may beincreased.

As another example, in the case of authentication (authentication of PTxby PRx) of the wireless power transmitting device by the wireless powerreceiving device, a procedure of determining whether the wireless powerreceiving device supports an authentication function of the wirelesspower transmitting device may be performed in the negotiation phase. Inthis case, before the negotiation phase, power transfer may be alreadyin progress based on an initial power contract. In the negotiationphase, by transmitting a query packet and determining a response to thequery packet, the wireless power receiving device may determine whetheran authentication function of the wireless power transmitting device issupported according to the procedure. In an aspect, the query packet maybe a general request packet (0x07), and in this case, when the wirelesspower receiving device transmits a general request packet to thewireless power transmitting device, the wireless power transmittingdevice transmits a capability packet including the auth of FIG. 14 or 15as the response to the wireless power receiving device. In anotheraspect, the query packet may be a specific request packet (0x20), and inthis case, when the wireless power receiving device transmits a specificrequest packet to the wireless power transmitting device, the wirelesspower transmitting device responds to ACK (when supporting anauthentication function) or NACK (when not supporting an authenticationfunction). In the negotiation phase, when it is determined that thewireless power transmitting device supports an authentication function,the wireless power receiving device may establish a power contract of 5W or more with the wireless power transmitting device (PC0).

When the wireless power receiving device determines authenticationfunction support of the wireless power transmitting device, theauthentication procedure may be finally started. More specifically,after the wireless power receiving device reaches a normal or stableoperation point that transmits a control error packet (CEP) in a periodof about 250 ms, the wireless power receiving device may perform anauthentication procedure with the wireless power transmitting device.During the power transfer phase, the authentication procedure may beused for renewing an existing power contract. That is, in order toincrease a power level according to the existing power contractaccording to the result of the authentication procedure, the wirelesspower receiving device may renegotiate the contract power. In this case,by transmitting a renegotiation packet (0x09), the wireless powerreceiving device may renew the contract power according to a powermanagement policy. For example, if the authentication procedure (withDIGEST) is successful, the wireless power receiving device may renew thecontract power with increased power or may maintain a current powercontract. If the authentication procedure is failed, the wireless powerreceiving device may renew the power contract with reduced power or mayremove a power signal.

As another example, in the case of authentication of the wireless powerreceiving device (authentication of PRx by PTx) by the wireless powertransmitting device, a procedure of determining whether the wirelesspower transmitting device supports an authentication function of thewireless power receiving device may be performed in an initializationphase. Here, the initialization phase may be a phase prior to anegotiation phase, for example, any one of a selection phase, a pingphase, and an identification and setting phase. In the initializationphase, in order to determine whether the wireless power receiving devicesupports an authentication function, the wireless power transmittingdevice receives a configuration packet including the auth of FIG. 16 or17 from the wireless power receiving device.

When the wireless power transmitting device determines authenticationfunction support of the wireless power receiving device, theauthentication procedure may be initiated in the negotiation phase. Inthis case, an initial power contract is signed. More specifically, thewireless power transmitting device stands by reception of DIGESTS fromthe wireless power receiving device. When the wireless powertransmitting device acknowledges that the wireless power receivingdevice has already authenticated, an authentication procedure issuccessful. When the wireless power transmitting device fails toacknowledge DIGESTS, the wireless power transmitting device continuesthe authentication procedure during the power transfer phase. Accordingto a power management policy, the wireless power transmitting deviceestablishes a power contract with the wireless power receiving device.In this case, the wireless power transmitting device may establish thecontract power of 5 W or more with the wireless power receiving device(PC0), having passed through authentication as DIGESTS. During the powertransfer phase, when the authentication procedure is completed, in orderto increase a power level, the wireless power transmitting device mayrenegotiate the power contract.

In the power transfer phase, after the wireless power receiving devicereaches a normal or stable operation point that transmits a CEP (0x03)in a period of about 250 ms, the wireless power transmitting device mayperform an authentication procedure with the wireless power receivingdevice. During the power transfer phase, the authentication proceduremay be used for renewing an existing power contract. That is, in orderto increase a power level according to the existing power contractaccording to the result of the authentication procedure, the wirelesspower receiving device may renegotiate the contract power. In this case,by transmitting a renegotiation packet (0x09), the wireless powerreceiving device may renew the contract power according to a powermanagement policy. For example, if the authentication procedure (withDIGEST) is successful, the wireless power receiving device may renew thecontract power with increased power or may maintain a current powercontract. However, if the authentication procedure is failed, thewireless power receiving device may renew the power contract withreduced power or may remove a power signal.

4. Authentication Procedures and Authentication Messages

Hereinafter, an authentication procedure and various messages used forthe authentication procedure will be described.

A message used in the authentication procedure is referred to as anauthentication message. The authentication message is used for carryinginformation related to authentication. There are two types ofauthentication messages. One message is an authentication request andthe other message is an authentication response. The authenticationrequest is transmitted by an authentication initiator, and theauthentication response is transmitted by an authentication responder.Both the wireless power transmitting device and receiving device may bean authentication initiator and an authentication responder. Forexample, when the wireless power transmitting device is anauthentication initiator, the wireless power receiving device becomes anauthentication responder, and when the wireless power receiving deviceis an authentication initiator, the wireless power transmitting devicebecomes an authentication responder.

The authentication request message includes GET_DIGESTS (i.e. 4 bytes),GET_CERTIFICATE (i.e. 8 bytes), and CHALLENGE (i.e. 36 bytes).

The authentication response message includes DIGESTS (i.e. 4+32 bytes),CERTIFICATE (i.e. 4+certificate chain (3×512 bytes)=1540 bytes),CHALLENGE_AUTH (i.e. 168 bytes), and ERROR (i.e. 4 bytes).

The authentication message may be referred to as an authenticationpacket and may be referred to as authentication data and authenticationcontrol information. Further, messages such as GET_DIGEST and DIGESTSmay be referred to as a GET_DIGEST packet and a DIGEST packet.

Hereinafter, a procedure in which the wireless power receiving deviceperforms authentication of the wireless power transmitting device basedon such authentication messages will be described.

(1) Authentication of the Wireless Power Transmitting Device by theWireless Power Receiving Device (Authentication of PTx by PRx)

When authentication (authentication of PTx by PRx) of the wireless powertransmitting device by the wireless power receiving device operatesbased on in-band communication, a required time for each step arerepresented in Table 6 or 7.

TABLE 6 Authentication Authentication initiator = PRx responder = PTxPhases Required time GET_DIGESTS Negotiation (4 + 3) × 11 × 0.5 = 38.5msec DIGESTS phase (36 + 2) × 11 × 5 = 2,090 msec GET_CERTIFICATE Power(8 + 3) × 11 × 0.5 = 60.5 msec CERTIFICATE transmission (1) 515 × 4 × 11× 5 = 113,300 phase msec = 1.8 min (for certificate) (2) 515 × (2B + 3)× 11 × 0.5 = 14,162.5 msec = 14 sec (for CE/ACK) CHALLENGE (36 + 3) × 11× 0.5 = 214.5 msec CHALLENGE_AUTH (1) 57 × 4 × 11 × 5 = 12,540 msec (forchallenge_auth) (2) 57 × (2B + 3) × 11 × 0.5 = 1,567.5 msec (for CE/ACK)

Table 6 represents an example of a time required for each authenticationmessage in the case where a power contract is made based on the resultsof GET_DIGESTS during the negotiation phase. When the wireless powerreceiving device already knows the DIGEST of the wireless powertransmitting device, a transmitting/receiving step of GET_CERTIFICATEand CERTIFICATE may be omitted. Further, a power contract may be renewedin a renegotiation phase according to the authentication result.

TABLE 7 Authentication Authentication initiator = PRx responder = PTxPhases Required time GET_DIGESTS Negotiation (1 + 3) × 11 × 0.5 = 22msec DIGESTS (or renegotiation) (32 + 2) × 11 × 5 = 1,870 msec phaseGET_CERTIFICATE Power (2 + 3) × 11 × 0.5 = 27.5 msec [Offset: Length]transmission phase {CE/RPP if CERTIFICATE (4 + 2) × 5 × 11 = 330 msecnecessary} . . . (for 4B reading) . . . (1 + 3) × 11 × 0.5 = 22 msec +30 msec = (for CE/delay/control time) = 55 msec 412. msec × (1536/4) =158,208 msec = 2.6 min CHALLENGE (32 + 3) × 11 × 0.5 = 192.5 msecGET_CHALLENGE_AUTH CHALLENGE_AUTH 27.5 msec (for Get_challenge_auth)[Offset: Length] . . . 330 msec (for 4B reading) {CE/RPP if 55 msec (forCE/delay/control time) necessary} 412 msec × (160/4) = 16,480 msec

Table 7 represents another example of a time required for eachauthentication message in the case where a power contract is made basedon the results of GET_DIGESTS during the negotiation phase. When thewireless power receiving device already knows DIGEST of the wirelesspower transmitting device, a transmitting/receiving step ofGET_CERTIFICATE and CERTIFICATE may be omitted. Further, a powercontract may be renewed in a renegotiation phase according to theauthentication result. Hereinafter, an authentication procedure forsatisfying the required time will be described.

FIG. 18 is a flowchart illustrating a sequence of transmitted andreceived packets when the wireless power receiving device performsauthentication (authentication of PTx by PRx) of the wireless powertransmitting device according to an embodiment.

Referring to FIG. 18, in order to obtain or retrieve certificate chainDIGESTS of the wireless power transmitting device, the wireless powerreceiving device transmits GET_DIGESTS to the wireless powertransmitting device (S1800). Here, it may be set to REQUEST=PTx'sDIGEST. Predefined operations for step S1800 may include an operation ofdetermining authentication function support in a capability packet inwhich the wireless power receiving device receives from the wirelesspower transmitting device. The wireless power receiving device maytransmit GET_DIGESTS to the wireless power transmitting device using ageneral request packet during the negotiation phase or the renegotiationphase. That is, the GET_DIGESTS may be loaded and transmitted in thegeneral request packet.

FIG. 19 illustrates an example of a message structure of GET_DIGESTS.Referring to FIG. 19, the GET_DIGESTS is configured with, for example, 1byte and includes a request field. The request field may indicate, forexample, a header of DIGEST of the wireless power transmitting device.

FIG. 20 illustrates another example of a message structure ofGET_DIGESTS. Referring to FIG. 20, the GET_DIGESTS is configured with,for example, 1 byte and includes reserved and a slot number. The slotnumber may identify a slot in which the requested certificate chain isstored and may be configured with, for example, 3 bits.

Referring again to FIG. 18, the wireless power transmitting devicetransmits DIGESTS in response to the GET_DIGESTS to the wireless powerreceiving device (S1805). The DIGESTS is used when the authenticationresponder transmits a report on certificate chain digests and a slotincluding valid certificate chain digests. A parameter of the DIGESTSmay be 32 bytes of a hash value of the certificate chain.

FIG. 21 illustrates a physical packet structure that transmits DIGESTSand a method of transmitting the physical packet structure. Referring toFIG. 21, the DIGESTS packet includes 32 bytes of DIGESTS payload, 1 byteof header representing that the corresponding packet is a packet onDIGESTS, and 2 bytes of header representing a length of thecorresponding packet. The wireless power transmitting device dividessuch a DIGESTS packet into a plurality of small packets of a specificlength (e.g., 3 bytes) and adds a checksum to the end of the smallpacket to transmit the small packet to a sequence of 4 bytes of DIGESTSsmall packet. A size of a last small packet of such a sequence may besmaller than 4 bytes. The small packet may be referred to as a segment.An illustration of FIG. 21 is to limit a size of a transmission packetof the wireless power transmitting device such that a singleauthentication response is configured with maximum 4 bytes. In this way,to divide a single response message into a series of small packets is toallow transmitting timing of a (extended) control error packet (CEP) anda (extended) received power packet (RPP) to be periodically (about 250ms) transmitted to the wireless power transmitting device by thewireless power receiving device, whereby foreign object detection and anoperating point for power transfer of the wireless power transmittingdevice may be efficiently managed.

Referring again to FIG. 18, when it is acknowledged that the wirelesspower transmitting device has already previously authenticated,authentication is successful. When the wireless power receiving devicedoes not acknowledge DIGESTS, the wireless power receiving devicecontinues to perform authentication during the power transfer phase.Steps S1800 and S1805 may be performed in the negotiation orrenegotiation phase. Alternatively, steps S1800 and S1805 may beperformed in the power transfer phase.

Thereafter, in order to obtain a certificate chain of the wireless powertransmitting device, the wireless power receiving device transmitsGET_CERTIFICATE to the wireless power transmitting device (S1810). Here,the GET_CERTIFICATE may be set by an offset and a length. TheGET_CERTIFICATE is used for reading a segment of a target certificatechain.

FIG. 22 illustrates an example of a message structure ofGET_CERTIFICATE. Referring to FIG. 22, the GET_CERTIFICATE is configuredwith, for example, two bytes and may include offset and length fields.Here, the offset is an offset from a start position of the certificatechain to a start position of a read request and an indication unitthereof is a byte. The length is a length of the read request and anindication unit thereof is a byte. For example, in order to read 4 bytesfrom a start position of the certificate chain, the offset [11 . . . 0]of the GET_CERTIFICATE may have a value of 00b, and a length thereof mayhave a value of 1 lb.

Referring again to FIG. 18, the wireless power transmitting devicetransmits at least a portion of the certificate chain to the wirelesspower receiving device in response to the GET_CERTIFICATE (S1815). Inthis case, a portion of the certificate chain may be initiated after anoffset from a time point initiated in a length of a byte unit.

FIG. 23 illustrates an example of a physical packet structure thattransmits a certificate and a method of transmitting the physical packetstructure. Referring to FIG. 23, when transmitting 1536 bytes ofcertificate packet, the wireless power transmitting device extracts acertificate having a length of 4 bytes from an offset point of thecertificate packet, adds a header indicating the certificate to thefront end of the certificate, and adds a checksum to the rear end of thecertificate to generate and transmit a certificate segment having total6 bytes of length.

FIG. 24 illustrates an example of a physical packet structure thattransmits an authentication response message of the wireless powertransmitting device and a method of transmitting the physical packetstructure. Referring to FIG. 24, a certificate packet (i.e. 1543 bytes)may include a certificate chain (i.e. 1540 bytes), a header (i.e. 1byte) indicating the certificate, and a header (i.e. 2 bytes) indicatinga length of the certificate packet. The wireless power transmittingdevice divides such a certificate packet into a plurality of smallpackets of a specific length (e.g., 3 bytes) and adds a checksum to theend of the small packet to transmit the small packet to a sequence of 4bytes of certificate small packets. In this case, each of total 515 datachunks is transmitted. A size of the last packet of the sequence may besmaller than 4 bytes. The small packet may be referred to as a segment.An illustration of FIG. 24 is to limit a size of a transmission packetof the wireless power transmitting device such that a singleauthentication response is configured with maximum 4 bytes. In this way,to divide a single response message into a series of small packets is toallow transmitting timing of a (extended) control error packet (CEP) anda (extended) received power packet (RPP) to be periodically (about 250ms) transmitted to the wireless power transmitting device by thewireless power receiving device, whereby foreign object detection and anoperating point for power transfer of the wireless power transmittingdevice may be efficiently managed.

Referring again to FIG. 18, if necessary, the wireless power receivingdevice may transmit a control error (CE) packet and/or a received powerpacket (RPP) to the wireless power transmitting device (S1820). StepsS1810 and S1820 may be performed, for example, in the power transferphase.

Thereafter, the wireless power receiving device may perform repeatedlysteps S1810 to S1820 until reading all certificate chains.

The wireless power receiving device transmits CHALLENGE to the wirelesspower transmitting device (S1825). The CHALLENGE is used for initiatingauthentication of a product.

FIG. 25 illustrates an example of a CHALLENGE message structure.Referring to FIG. 25, the CHALLENGE is configured with, for example, 32bits (4 bytes) and may include four Nonce fields. Nonce is a binaryrandom number selected by the authentication initiator.

Referring again to FIG. 18, in order to obtain CHALLENGE_AUTH, thewireless power receiving device transmits GET_CHALLENGE_AUTH to thewireless power transmitting device (S1830). Here, the GET_CHALLENGE_AUTHmay be set to an offset and a length.

The wireless power transmitting device transmits a portion ofCHALLENGE_AUTH in response to the GET_CHALLENGE_AUTH to the wirelesspower receiving device (S1835). In this case, a portion of theCHALLENGE_AUTH may be initiated after an offset from a time pointinitiated in a length of a byte unit.

FIG. 26 illustrates an example of a physical packet structure thattransmits CHALLENGE_AUTH and a method of transmitting the physicalpacket structure. Referring to FIG. 26, the CHALLENGE_AUTH packet (i.e.160 bytes) may include a certificate chain hash (i.e. 32 bytes), Salt(i.e. 32 bytes), a context hash (i.e. 32 bytes), and a signature (i.e.64 bytes). The wireless power transmitting device extracts a specificlength (e.g., 4 bytes) from the offset of such a CHALLENGE_AUTH packetbased on the offset and the length indicated in the CHALLENGE_AUTHpacket, adds a header indicating the CHALLENGE_AUTH packet to the frontend thereof, and adds a checksum to the rear end thereof to generate andtransmit a certificate segment having total 6 bytes of length.

Referring again to FIG. 18, if necessary, the wireless power receivingdevice may transmit the control error (CE) packet and/or the receivedpower packet (RPP) to the wireless power transmitting device (S1840).

Thereafter, the wireless power receiving device may perform repeatedlysteps S1830 to S1840 until reading all CHALLENGE_AUTHs.

Hereinafter, a procedure in which the wireless power transmitting deviceperforms authentication of the wireless power receiving device based onthe authentication message will be described.

(2) Authentication of the Wireless Power Receiving Device by theWireless Power Transmitting Device (Authentication of PRx by PTx)

When authentication (authentication of PRx by PTx) of the wireless powerreceiving device by the wireless power transmitting device operatesbased on in-band communication, a time required for each step are shownin Table 8 or 9.

TABLE 8 Authentication Authentication initiator = PTx responder = PRxPhases Required time GET_DIGESTS Negotiation (4 + 2) × 11 × 5 = 330 msecDIGESTS phase (36 + 3) × 11 × 0.5 = 214.5 msec GET_CERTIFICATE Power(8 + 2) × 11 × 5 = 550 msec CERTIFICATE transmission (1) 41 × 40 × 11 ×0.5 = 9020 msec phase (for certificate) (2) 41 × 40 = 1640 msec = 1.6sec (for ACK) (assuming no CE packets are sent) CHALLENGE (36 + 2) × 11× 5 = 2090 msec CHALLENGE_AUTH (1) 5 × 40 × 11 × 0.5 = 1100 msec (forchallenge_auth) (2) 5 × 40 = 200 msec (for ACK)

Table 8 represents an example of a time required for each authenticationmessage in the case where a power contract is made based on the resultsof GET_DIGESTS during the negotiation phase. When the wireless powertransmitting device already knows the DIGEST of the wireless powerreceiving device, a transmitting/receiving step of GET_CERTIFICATE andCERTIFICATE may be omitted. Further, a power contract may be renewed ina renegotiation phase according to the authentication result.

TABLE 9 Authentication Authentication initiator = PTx responder = PRxPhases Required time DIGESTS Negotiation (32 + 3) × 11 × 0.5 = 192.5msec phase CE Power (1 + 3) × 11 × 0.5 = 22 msec transmission phaseReqest_COMM ACK Power (1) 8 × 5 = 40 ms (Request for Comm.)GET_CERTIFICATE Certificate transfer (2) (1 + 3) × 11 × 0.5 = 22 ms(ACK) phase (3) (2 + 2) × 11 × 5 = 220 ms (Get_Certificate) (3) (40 + 3)× 11 × 0.5 = 236.5 ms (Certificate) (4) 540.5 × 39 = 21079.5 ms = 21 s(assuming sending certificate by 40 Bytes) CE (1 + 3) × 11 × 0.5 = 22 msReqest_COMM ACK (1) 8 × 5 = 40 ms (Request for Comm.) CHALLENGE [n], ACK(2) (1 + 3) × 11 × 0.5 = 22 ms (ACK) n = 0 . . . 7 (3) (4 + 2) × 11 × 5= 330 ms (Challenge) (4) (1 + 3) × 11 × 0.5 = 22 ms (ACK) (5) 436 × 8 =3488 ms = 3 s (assuming sending Challenge by 4 Bytes) CE (1 + 3) × 11 ×0.5 = 22 ms Reqest_COMM ACK (1) 8 × 5 = 40 ms (Request for Comm.)GET_CHALLENGE_AUTH CHALLENGE_AUTH (2) (1 + 3) × 11 × 0.5 = 22 ms (ACK)[n] (3) (2 + 2) × 11 × 5 = 220 ms (Get_Challenge_Auth) (4) (40 + 3) × 11× 0.5 = 236.5 ms (Challenge_Auth) (5) 540.5 × 4 = 2162 ms = 2 s(assuming sending Challenge_Auth by 40 Bytes)

Table 9 represents an example of a time required for each authenticationmessage in the case where a power contract is made based on the resultsof GET_DIGESTS during the negotiation phase. When the wireless powertransmitting device already knows DIGEST of the wireless power receivingdevice, a control error packet transmission step, a communicationrequest step, and a transmitting/receiving step of the GET_CERTIFICATEand the CERTIFICATE may be omitted. Further, a power contract may berenewed in a renegotiation phase according to the authentication result.Hereinafter, an authentication procedure for satisfying the requiredtime will be described.

FIG. 27 is a flowchart illustrating a sequence of transmitted andreceived packets when the wireless power transmitting device performsauthentication (authentication of PRx by PTx) of the wireless powerreceiving device according to an embodiment.

Referring to FIG. 27, the wireless power transmitting device receivesDIGESTS transmitted from the wireless power receiving device (S2700).DIGESTS is used when the authentication responder transmits a report oncertificate chain digests and a slot including valid certificate chaindigests. A parameter of DIGESTS may be 32 bytes of a hash value of thecertificate chain. Predefined operations for step S2700 may include anoperation of determining authentication function support in a capabilitypacket in which the wireless power receiving device receives from thewireless power transmitting device and an operation in which thewireless power transmitting device transmits GET_DIGESTS to the wirelesspower receiving device. Step S2700 may be performed in a negotiation orrenegotiation phase, or a power transfer phase.

FIG. 28 illustrates an example of a message structure of GET_DIGESTStransmitted by the wireless power transmitting device. Referring to FIG.28, GET_DIGESTS is configured with, for example, 1 byte and includes arequest field. The GET_DIGESTS includes reserved and a slot number. Theslot number identifies a slot in which a requested certificate chain isstored and may be configured with, for example, 3 bits.

Referring again to FIG. 27, during the power transfer phase, thewireless power receiving device transmits a control error packet and areceived power packet to the wireless power transmitting device (S2705).

The wireless power transmitting device transmits a request forcommunication in response to the control error packet or the receivedpower packet (S2710). The request for communication may be, for example,a bit pattern response.

When the wireless power receiving device responds to ACK to the requestfor communication (S2715), in order to obtain a certificate chain or aCHALLENGE_AUTH response of the wireless power receiving device, thewireless power transmitting device transmits GET_CERTIFICATE to thewireless power receiving device (S2720). Here, the GET_CERTIFICATE maybe set by an offset and a length. The GET_CERTIFICATE is used forreading a segment of a target certificate chain.

FIG. 29 illustrates an example of a GET_CERTIFICATE message structure inwhich the wireless power transmitting device transmits. Referring toFIG. 29, the GET_CERTIFICATE is configured with, for example, 2 bytesand may include offset and length fields. Here, the offset is an offsetfrom a start position of the certificate chain to a start position of aread request and an indication unit thereof is a byte. The length is alength of the read request and an indication unit thereof is a byte. Forexample, in order to read 40 bytes from a start position of thecertificate chain, an offset [7 . . . 0] of GET_CERTIFICATE may have avalue of 00b, and a length thereof may have a value of 110000b.

Referring again to FIG. 27, the wireless power receiving devicetransmits at least a portion of the certificate chain to the wirelesspower transmitting device in response to the GET_CERTIFICATE (S2725). Inthis case, a portion of the certificate chain may be initiated after anoffset from a time point initiated in a length of a byte unit.

FIG. 30 illustrates an example of a physical packet structure in which acertificate of a wireless power receiving device is transmitted and amethod of transmitting the physical packet structure. Referring to FIG.30, when transmitting 1536 bytes of certificate packet, the wirelesspower receiving device extracts a certificate of a length 40 bytes froman offset point of the certificate packet, adds a header (i.e., 1 byte)indicating the certificate to the front end thereof, and adds a checksum(i.e., 1 byte) to the rear end thereof to generate and transmit acertificate segment having a length of total 42 bytes.

Referring again to FIG. 27, the wireless power transmitting device mayrepeatedly perform steps S2710 to S2725 until reading all certificatechains.

If necessary, the wireless power receiving device may transmit a controlerror (CE) packet and/or a received power packet (RPP) to the wirelesspower transmitting device (S2730).

The wireless power transmitting device transmits a request forcommunication in response to the CE packet and the RPP (S2735). Therequest for communication may be, for example, a bit pattern response.

When the wireless power receiving device responds to ACK to the requestfor communication (S2740), the wireless power transmitting devicetransmits CHALLENGE [n] to the wireless power receiving device (S2745).CHALLENGE is used for initiating authentication of the product.

FIG. 31 illustrates an example of a CHALLENGE message structure in whichthe wireless power transmitting device transmits. Referring to FIG. 31,CHALLENGE is configured with, for example, 32 bits (4 bytes) and mayinclude four Nonce fields. The Nonce is a binary random number selectedby the authentication initiator. By transmitting 8 CHALLENGE packets,the wireless power transmitting device may provide total 32 bytes ofNonce to the wireless power receiving device.

Referring again to FIG. 27, after receiving ACK from the wireless powerreceiving device, the wireless power transmitting device may performrepeatedly steps S2735 to S2750 until transmitting all CHALLENGEs.

The wireless power receiving device may transmit a control error packetand/or a received power packet to the wireless power transmitting device(S2755). The wireless power transmitting device transmits a request forcommunication in response to the control error packet and the receivedpower packet (S2760). The request for communication may be, for example,a bit pattern response.

When the wireless power receiving device responds to ACK to the requestfor communication (S2765), in order to obtain CHALLENGE_AUTH, thewireless power transmitting device transmits GET_CHALLENGE_AUTH to thewireless power receiving device (S2770). Here, GET_CHALLENGE_AUTH may beset to an offset and a length.

The wireless power receiving device transmits at least a portion ofCHALLENGE_AUTH to the wireless power transmitting device in response tothe GET_CHALLENGE_AUTH (S2775). In this case, at least a portion ofCHALLENGE_AUTH may be initiated after an offset from a time pointinitiated in a length of a byte unit.

FIG. 32 illustrates an example of a physical packet structure in whichCHALLENGE_AUTH of the wireless power receiving device is transmitted anda method of transmitting the physical packet structure. Referring toFIG. 32, a CHALLENGE_AUTH packet (i.e. 160 bytes) may include acertificate chain hash (i.e. 32 bytes), Salt (i.e. 32 bytes), a contexthash (i.e. 32 bytes), and a signature (i.e. 64 bytes). The wirelesspower transmitting device extracts a specific length (e.g., 40 bytes)from the offset of such a CHALLENGE_AUTH packet based on the offset andthe length indicated in GET_CHALLENGE_AUTH, adds a header (i.e. 1 byte)indicating the CHALLENGE_AUTH packet to the front end thereof, and addsa checksum (i.e. 1 byte) to the rear end thereof to generate andtransmit a certificate segment having a length of total 42 bytes.

Thereafter, the wireless power transmitting device may repeatedlyperform from steps S2760 to S2775 until reading all CHALLENGE_AUTH.

FIG. 33 illustrates an example of a physical packet structure in whichan authentication response message of a wireless power receiving deviceis transmitted and a method of transmitting the physical packetstructure. Referring to FIG. 33, for example, a certificate packet (i.e.N bytes) may include a certificate chain, a header (i.e. 1 byte)indicating the certificate, and a header (i.e. 2 bytes) indicating alength of a certificate packet. The wireless power receiving devicedivides such a certificate packet into a plurality of small packets of aspecific length (e.g., M−1 bytes) and adds a checksum of 1 byte to theend of small packets to transmit the packet to a sequence of M bytes ofcertificate small packets. A size of a last small packet of the sequencemay be smaller than M bytes. The small packet may be referred to as asegment. An illustration of FIG. 33 is to limit a size of a transmissionpacket of the wireless power receiving device such that a singleauthentication response is configured with M bytes. To divide a singleresponse message into a series of small packets is to allow timing inwhich the wireless power receiving device transmits a (extended) controlerror packet (CEP) and a (extended) received power packet (RPP) to beperiodically (about 250 ms) transmitted to the wireless power transferdevice, whereby foreign object detection and an operating point forpower transfer of the wireless power transmitting device may beefficiently managed.

FIG. 34 illustrates another example of a physical packet structure inwhich an authentication response message of a wireless power receivingdevice is transmitted and a method of transmitting the physical packetstructure. Referring to FIG. 34, for example, a certificate packet (i.e.1543 bytes) may include a certificate chain (i.e. 1540 bytes), a header(i.e. 1 byte) indicating the certificate, and a header (i.e. 2 bytes)indicating a length of a certificate packet. The wireless powerreceiving device divides such a certificate packet into a plurality ofsmall packets of a specific length (e.g., 38 bytes), adds a preamble(i.e. 1 byte) to the front end of small packets, and adds a checksum(i.e. 1 byte) to the rear end of small packets to transmit the packet toa sequence of 40 bytes of certificate small packets. In this case, eachof total 41 data chunks is transmitted. A size of a last small packet ofthe sequence may be smaller than 40 bytes. The small packet may bereferred to as a segment. An illustration of FIG. 34 is to limit a sizeof the transmission packet of the wireless power receiving device suchthat a single authentication response is configured with 40 bytes. Todivide a single response message into a series of small packets is toallow timing in which the wireless power receiving device transmits a(extended) control error packet (CEP) and a (extended) received powerpacket (RPP) to be periodically (about 250 ms) transmitted to thewireless power transfer device, whereby foreign object detection and anoperating point for power transfer of the wireless power transmittingdevice may be efficiently managed.

FIG. 35 is a flowchart illustrating a sequence of transmitted andreceived packets when the wireless power transmitting device performsauthentication (authentication of PRx by PTx) of a wireless powerreceiving device according to another embodiment.

Referring to FIG. 35, the wireless power transmitting device receivesDIGESTS transmitted from the wireless power receiving device (S3500).Predefined operations for step S3500 may include an operation in whichthe wireless power receiving device determines authentication functionsupport in a capability packet received from the wireless powertransmitting device and an operation in which the wireless powertransmitting device transmits GET_DIGESTS to the wireless powerreceiving device. Step S3500 may be performed in a negotiation phase ora power transfer phase.

During the power transfer phase, the wireless power receiving devicetransmits the CEP and the RPP to the wireless power transmitting device(S3505).

The wireless power transmitting device transmits a request for multiplecommunications in response to the CEP and the RPP (S3510). The requestfor multiple communications may be, for example, a bit pattern response.

When the wireless power receiving device responds to ACK to the requestfor multiple communications (S3515), in order to obtain a certificatechain or a CHALLENGE_AUTH response of the wireless power receivingdevice, the wireless power transmitting device transmits GET_CERTIFICATEto the wireless power receiving device (S3520). Here, theGET_CERTIFICATE may be set by an offset and a length. TheGET_CERTIFICATE is used for reading a segment of a target certificatechain.

The wireless power receiving device transmits at least a portion of thecertificate chain to the wireless power transmitting device in responseto the GET_CERTIFICATE (S3525). In this case, a portion of thecertificate chain may be initiated after an offset from a time pointinitiated in a length of a byte unit.

The wireless power transmitting device may repeatedly perform stepsS3520 to S3525 until reading all certificate chains.

If necessary, the wireless power receiving device may transmit a controlerror (CE) packet and/or a received power packet (RPP) to the wirelesspower transmitting device (S3530).

The wireless power transmitting device transmits a request for multiplecommunications in response to the CE packet and the RPP (S3535). Therequest for multiple communications may be, for example, a bit patternresponse.

When the wireless power receiving device responds to ACK to the requestfor multiple communications (S3540), the wireless power transmittingdevice transmits CHALLENGE[n] to the wireless power receiving device(S3545). The CHALLENGE is used for initiating authentication of aproduct.

The wireless power transmitting device receives ACK from the wirelesspower receiving device (S3550) and may repeatedly perform steps S3545 toS3550 until transmitting all CHALLENGEs.

The wireless power receiving device may transmit the CE packet and/orthe RPP to the wireless power transmitting device (S3555). The wirelesspower transmitting device transmits a request for multiplecommunications in response to the CE packet and the RPP (S3560). Therequest for multiple communications may be, for example, a bit patternresponse.

When the wireless power receiving device responds to ACK to the requestfor multiple communications (S3565), in order to obtain CHALLENGE_AUTH,the wireless power transmitting device transmits GET_CHALLENGE_AUTH tothe wireless power receiving device (S3570). Here, theGET_CHALLENGE_AUTH may be set to an offset and a length.

The wireless power receiving device transmits at least a portion ofCHALLENGE_AUTH in response to the GET_CHALLENGE_AUTH to the wirelesspower transmitting device (S3575). In this case, at least a portion ofCHALLENGE_AUTH may be initiated after an offset from a time pointinitiated in a length of a byte unit.

Thereafter, the wireless power transmitting device may repeatedlyperform steps S3570 to S3575 until reading all CHALLENGE_AUTHs.

5. Lower Level Protocol that Supports Authentication Procedure

Because a packet transmission protocol of a low level that supports anauthentication procedure may be configured based on in-bandcommunication, it is necessary to configure a packet structure used inin-band communication to be appropriate to the authentication procedureand the authentication message.

FIG. 36 illustrates a structure of a packet in which the wireless powerreceiving device transmits to the wireless power transmitting devicein-band communication. A packet according to FIG. 36 may be modulated byan ASK scheme.

Referring to FIG. 36, a bit rate is 2 Kbps, and the packet includes apreamble, a header, a message, and a checksum. For example, the preamblemay be set to 11 bits, the header may be set to 1B, and the checksum maybe set to 1B (1B->1 lbits).

FIG. 37 illustrates a structure of a packet in which the wireless powertransmitting device transmits to the wireless power receiving devicein-band communication. The packet according to FIG. 37 may be modulatedby an FSK scheme.

Referring to FIG. 37, a bit rate in an operation frequency of 100 kHz is200 bps, and the packet includes a header, a message, and a checksum.For example, the header may be set to 1B, and the checksum may be set to1B (1B->11 bits).

(1) Low Level Authentication Sequence

1) Authentication of the Wireless Power Transmitting Device by theWireless Power Receiving Device (Authentication of PTx by PRx)

When the wireless power receiving device is an authentication initiator,the wireless power transmitting device becomes an authenticationresponder. Alternatively, the wireless power transmitting device may berepresented with a (authentication) target device. As the authenticationinitiator, the wireless power receiving device transmits a message (orpacket) necessary for authentication of the wireless power transmittingdevice as a message (or packet) that requests to the wireless powertransmitting device. As an authentication responder, the wireless powertransmitting device transmits an authentication response messageconfigured with a sequence of several packets to the wireless powerreceiving device. A transmitting and receiving process of such a seriesof messages may be defined by a packet transmission protocol of a lowerlevel.

FIG. 38 illustrates a transmission and reception sequence of a packetbetween a wireless power receiving device and transmitting device from alower level viewpoint according to an embodiment. FIG. 38 illustrates aprocess in which the wireless power transmitting device transmits anauthentication response packet (DIGESTS) to the wireless power receivingdevice when the wireless power receiving device transmits GET_DIGESTS tothe wireless power transmitting device.

Referring to FIG. 38, after transmitting every packet of a sequence, thewireless power transmitting device stands by transmission of ACK/NACK orcontinue/stop from the wireless power receiving device. ACK/NACK orcontinue/stop is included and transmitted in the (extended) CEP of FIG.39. Until transmitting all packets of the sequence, the wireless powertransmitting device and/or the wireless power receiving device repeat(s)the following procedure.

> If the wireless power transmitting device receives “ACK and continue”,the wireless power transmitting device transmits a next packet.

> If the wireless power transmitting device receives “ACK and stop”, thewireless power transmitting device stands by until receiving a nextextended CEP including “ACK and continue”.

> If the wireless power transmitting device receives “NACK andcontinue”, the wireless power transmitting device retransmits a previouspacket.

> If the wireless power transmitting device receives “NACK and stop”,the wireless power transmitting device stands by until receiving a nextextended CEP including “ACK and continue”.

FIG. 39 illustrates a transmission and reception sequence of a packetbetween a wireless power receiving device and transmitting device from alower level viewpoint according to another embodiment. FIG. 39illustrates a process in which the wireless power transmitting devicereceives an authentication response packet (CERTIFICATE) to the wirelesspower receiving device when the wireless power receiving devicetransmits GET_CERTIFICATE to the wireless power transmitting device.

Referring to FIG. 39, after transmitting every packet of the sequence,the wireless power transmitting device stands by transmission ofACK/NACK or continue/stop from the wireless power receiving device.ACK/NACK or continue/stop is included and transmitted in the extendedCEP of FIG. 39. The wireless power transmitting device and/or receivingdevice repeat(s) the following procedure until transmitting all packetsof the sequence.

> If the wireless power transmitting device receives “ACK and continue”,the wireless power transmitting device transmits a next packet. Forexample, for a packet 1, the wireless power transmitting device mayreceive “ACK and continue” through the extended CEP, and for a packet m,the wireless power transmitting device may receive “ACK and continue”through the extended RPP of FIG. 42.

> If the wireless power transmitting device receives “ACK and stop”, thewireless power transmitting device stands by until receiving a nextextended CEP including “ACK and continue”. For example, for a packet n,the wireless power transmitting device receives “ACK and stop” throughan extended CEP.

> If the wireless power transmitting device receives “NACK andcontinue”, the wireless power transmitting device retransmits a previouspacket.

> If the wireless power transmitting device receives “NACK and stop”,the wireless power transmitting device stands by until receiving a nextextended CEP including “ACK and continue”.

FIG. 40 illustrates a structure of the extended CEP according to anembodiment.

Referring to FIG. 40, the wireless power receiving device transmits theextended CEP in response to the packet of the wireless powertransmitting device. In this case, the extended CEP includes at leastone of ACK/NACK or continue/stop as well as a control error value thatadjusts an operating point of the wireless power transmitting device.

For example, the stop is configured with 1 bit, and when a value thereofis ‘1’b, it indicates that the wireless power transmitting device stopstransmission of a packet, and when a value thereof is ‘0’b, it indicatesthat the wireless power transmitting device transmits (i.e., continue oftransmission) a next packet of a sequence. Here, in order for thewireless power receiving device to quickly adjust an operating point ofthe wireless power transmitting device, when it is necessary to transmita CEP with a short period or when receiving all response packets, thewireless power receiving device may set stop to 1 to enforce thewireless power transmitting device to suspend transmission of a packetin a next sequence.

ACK/NACK is configured with, for example, 4 bit, and when a valuethereof is ‘0000’b, the value may indicate ACK, and when a value thereofis ‘1111’b, the value may indicate NACK. ACK represents that thewireless power receiving device successfully receives a packet withoutan error condition, and NACK represents that the wireless powerreceiving device requests retransmission of a packet to the wirelesspower transmitting device due to occurrence of a packet reception error.

FIG. 41 illustrates a structure of an end power transfer (EPT) packetaccording to an embodiment.

Referring to FIG. 41, the EPT packet corresponding to a header value0x02 may indicate a code value required for an authentication procedure.For example, when authentication of the wireless power transmittingdevice is failed, the wireless power receiving device may set an EPTcode value to indicate a code value different from an existing codevalue as in 0x0E. By transmitting a new EPT code value, the wirelesspower receiving device may remove power transfer.

FIG. 42 illustrates a structure of the extended received power packetaccording to an embodiment.

Referring to FIG. 42, the extended received power packet is configuredwith 24 bits and may include a first reserved bit, a mode, a receivedpower value, a second reserved bit, stop, and ACK/NACK. That is, theextended received power packet includes a received power value relatedto FOD of the wireless power transmitting device and includes at leastone of ACK/NACK or continue/stop.

For example, the stop is configured with 1 bit, and when a value thereofis ‘1’b, the wireless power transmitting device stops transmission of apacket, and when a value thereof is ‘0’b, the wireless powertransmitting device transmits (i.e., continue of transmission) a nextpacket of a sequence. Here, in order for the wireless power receivingdevice to quickly adjust an operating point of the wireless powertransmitting device, when it is necessary to transmit a CEP with a shortperiod or when receiving all response packets, the wireless powerreceiving device may set stop to 1 to enforce the wireless powertransmitting device to suspend transmission of a packet in a nextsequence.

ACK/NACK is configured with, for example, 4 bits, and when a valuethereof is ‘0000’b, the value may indicate ACK, and when a value thereofis ‘1111’b, the value may indicate NACK. ACK represents that thewireless power receiving device successfully receives a packet withoutan error condition, and NACK represents that the wireless powerreceiving device requests retransmission of a packet to the wirelesspower transmitting device due to occurrence of a packet reception error.

2) Authentication of the Wireless Power Receiving Device by the WirelessPower Transmitting Device (Authentication of PRx by PTx)

When the wireless power transmitting device is an authenticationinitiator, the wireless power receiving device becomes an authenticationresponder. Alternatively, the wireless power receiving device may berepresented with a (authentication) target device. As an authenticationinitiator, the wireless power transmitting device transmits a message(or packet) required for authentication of the wireless power receivingdevice as a message (or packet) requesting to the wireless powerreceiving device. An authentication responder, the wireless powerreceiving device transmits an authentication response message configuredwith a sequence of several packets to the wireless power transmittingdevice. A transmitting and receiving process of such a series ofmessages may be defined by a packet transmission protocol of a lowerlevel.

FIG. 43 illustrates a transmission and reception sequence of a packetbetween the wireless power receiving device and transmitting device froma lower level viewpoint according to an embodiment. FIG. 43 illustratesa process in which the wireless power receiving device transmits anauthentication response packet (CERTIFICATE) to the wireless powertransmitting device when the wireless power transmitting devicetransmits GET_CERTIFICATE to the wireless power receiving device.

Referring to FIG. 43, after transmitting every packet of the sequence,the wireless power receiving device stands by transmission of ACK/NACK(bit-pattern response) from the wireless power transmitting device. Abit response time may be, for example, 40 ms. The wireless powertransmitting device and/or receiving device may repeat the followingprocedure until transmitting all packets of the sequence. Between theauthentication response packets, the wireless power receiving device maytransmit the CEP and/or the RPP.

> If the wireless power receiving device receives ‘ACK’, the wirelesspower receiving device transmits a next packet. For example, for apacket 1, when the wireless power receiving device receives ACK, thewireless power receiving device transmits a packet 2 at nexttransmission timing.

> If the wireless power receiving device receives ‘NACK’, the wirelesspower receiving device retransmits a previous packet.

(2) Protocol for Data Transaction in a Lower Level

Hereinafter, a data transaction protocol will be described. For datatransaction in a lower level, the present embodiment may consider fourrules.

Rule 1 is that the wireless power receiving device operates as a master.When the wireless power receiving device operates as a master and thewireless power transmitting device operates as a slave, the wirelesspower receiving device determines when communication of the wirelesspower transmitting device is allowed.

The wireless power receiving device may transmit a start of data stream(SOD) ADT_CTRL packet to inquire whether there is data stream in whichthe wireless power transmitting device is to transmit. Alternatively, inorder to pool to the wireless power transmitting device on whether thereis a packet in which the wireless power transmitting device is totransmit, the wireless power receiving device may transmit a generalrequest packet (GRP) in which a request is set to ‘0xFF’.

Rule 2 is communication error control. The wireless power receivingdevice or transmitting device may rewrite an ADT packet until receivingACK. Further, when a communication error does not occur, an “ACK”ADT_CTRL packet is transmitted, and when a communication error isdetected, a “NACK” ADT_CTRL packet is transmitted.

Rule 3 is synchronization of data stream. For synchronization, whenevera new data packet is transmitted, a header of the ADT data packet may betoggled.

Rule 4 is to mark the end of data stream or to mark the end and thestart of data stream. Specifically, a start of the data stream (SOD)ADT_CTRL packet may be added to the start of the data stream.Alternatively, an end of data stream (EOD) ADT_CTRL packet may be addedto the end of the data stream. Here, the SOD and the EOD may be addedwhen a length of the data stream is greater than 1 packet.

Data transport and a packet structure based on the above rules may bedefined as follows.

1) Data Transport and Packet Structure of a Lower Level forAuthentication

Hereinafter, low level data transport and packet structure forauthentication will be described in detail. Two design methods of thelow level data transport include a dedicated mapping method and ageneric bit pipe method. The generic bit pipe method has the advantagethat the generic bit pipe method provides application-agnostic datatransmission and may be used for other applications in the future inaddition to authentication.

Design requirements for a general bit pipe based low level datatransport is i) to minimize an interaction between a high level and alow level and ii) to ensure an error-recovery and synchronized low leveldata transport. In relation to i), a higher level encodes data stream topush the data stream to a lower level (write) and decodes the datastream provided from the low level (read). Further, the lower levelwrites or reads data stream using a plurality of auxiliary datatransport (ADT) data packets (write/read). In relation to ii), a simpleand robust communication-error-recovery mechanism include an operatingof rewriting an ADT packet until the wireless power transmitting deviceor receiving device receives ACK and an operating of re-reading the ADTpacket until there is no communication error. Further, simplesynchronization of data stream between the wireless power transmittingdevice and receiving device includes an operation of toggling a headerof the data packet when transporting a new ADT data packet.

FIG. 44 illustrates data transport according to an embodiment. FIG. 44illustrates update transport data (UDT).

Referring to FIG. 44, UDT is used for carrying update data. The updatedata includes some data packets. For example, the update data mayinclude a control error packet (CEP), a received power packet (RPP)optionally including ACK or NACK, auxiliary data transport (ADT), acharge status packet (CSP), a proprietary packet, a renegotiation (RNG)packet optionally including ACK or NACK, and a reserved packet (thewireless power transmitting device should be resilient to reservedbits).

The ADT is a low level data packets or transport for a higher levelapplication and includes the same logical layer packet as that of acapability packet of the wireless power transmitting device.

FIG. 45 illustrates data transport according to another embodiment. FIG.45 illustrates auxiliary data transport (ADT).

Referring to FIG. 45, the ADT includes ADT (ADT_PRx) of the wirelesspower receiving device and ADT (ADT_PTx) of the wireless powertransmitting device.

The ADT of the wireless power receiving device carries data, a response(e.g., ACK, NACK, RFA) packet, or a control packet from the wirelesspower receiving device.

The ADT of the wireless power transmitting device carries data, aresponse (e.g., ACK, NACK, RFA) packet, a control packet, or anACK/NACK/RFA bit pattern response from the wireless power transmittingdevice.

As an example, the header of the ADT packet may indicate a lower leveldata packet for a higher level application (e.g., a low level datapacket of the wireless power receiving device and a low level datapacket of the wireless power transmitting device). The higher levelapplication may include, for example, an authentication procedure,proprietary information exchange, firmware update, and power capabilitycontrol of the wireless power transmitting device.

As another example, the header of the ADT packet may indicate a logicallayer data packet (e.g., a packet of the wireless power receiving deviceor a packet of the wireless power transmitting device). As anotherexample, the header of the ADT packet may include a control packet.

As another example, the header of the ADT packet may indicate an ADTdata packet, and in this case, the header of the ADT data packet mayinclude multiple types of headers (e.g., two types of headers such as aheader A and a header B). Whenever a new ADT data packet is transmitted,the header of the ADT data packet is toggled to A->B or B->A and thussynchronization of the data stream may be achieved.

As another example, the header of the ADT packet may indicate an ADTcontrol packet, and in this case, the header of the ADT packet mayinclude a single type of header.

Hereinafter, an ADT packet structure as low level data transport will bedescribed. As described above, the ADT is configured with a pair of ADT(ADT_PRx) of the wireless power receiving device and ADT (ADT_PTx) ofthe wireless power transmitting device, and the ADT (ADT_PRx) of thewireless power receiving device will be first described.

FIG. 46 illustrates a structure of an ADT data packet (ADT_PRx datapacket) of the wireless power receiving device according to anembodiment.

Referring to FIG. 46, the ADT data packet includes, for example, (n+1)bytes of payload, and each payload may correspond to any one of aplurality of header types. Table 10 represents a correspondingrelationship between a header and a payload size (when n=15, maximum 16bytes) of the ADT data packet.

TABLE 10 Payload Size (byte) Header A Header B 1 0x1C 0x1D 2 0x2C 0x2D 30x3C 0x3D 4 0x4C 0x4D . . . . . . . . . 13  0xAC  0xAD 14 0xB4 0xB5 15 0xBC  0xBD 16 0xC4 0xC5

Referring to Table 10, when a payload of a particular byte is includedand transmitted in the ADT data packet, a header A or B may be used. Apayload size may be 1 byte to 16 bytes. When transmitting a new datapacket and retransmitting an immediately preceding ADT data packet, thewireless power receiving device and the wireless power transmittingdevice specifically promise a pattern of a header value to pursuesynchronization therebetween. For example, in a situation in which thewireless power receiving device transmits 1 byte of payload to the ADTdata packet, when the wireless power receiving device transmits a newADT data packet, the wireless power receiving device toggles a headervalue from the header A (=0x1C) to the header B (=0x1D) or from theheader B (=0x1D) to the header A (=0x1C), and when the wireless powerreceiving device retransmits the immediately preceding ADT data packet,the wireless power receiving device may maintain an immediatelypreceding header value. A situation of retransmitting the immediatelypreceding ADT data packet may be when the wireless power receivingdevice receives a NACK response from the wireless power transmittingdevice or when the wireless power receiving device finds a decodingerror of the wireless power transmitting device.

FIG. 47 illustrates a structure of an ADT response packet (ADT_PRxresponse packet) of the wireless power receiving device according to anembodiment.

Referring to FIG. 47, the ADT response packet of the wireless powerreceiving device is configured with, for example, 1 byte, and a valuethereof may indicate ACK, NACK, and RFA. Table 11 represents thecorresponding relationship between a payload value of the ADT responsepacket and indication content thereof.

TABLE 11 Payload value Indication content ‘11111111’b ACK ‘00000000’bNACK ‘00110011’b RFA

In Table 11, when a payload value is ‘11111111’b, the payload valuerepresents that the wireless power receiving device has successfullyreceived and decoded the ADT data packet transmitted by the wirelesspower transmitting device at an immediately preceding ADT (ACK). Whenthe payload value is ‘00000000’b, the payload value represents that thewireless power receiving device has not successfully received anddecoded the ADT data packet transmitted by the wireless powertransmitting device at an immediately preceding ADT (NACK). In thiscase, the wireless power transmitting device retransmits the immediatelypreceding ADT data packet at a current ADT, and in this case, the headerof the ADT data packet has a value corresponding to retransmission ofthe immediately preceding data packet (e.g., 0x1C). When the payloadvalue is ‘00110011’b, the payload value represents that the wirelesspower receiving device requests to transmit response data to thewireless power transmitting device (RFA). In Table 11, the payload valueand instruction content thereof are an example, and as a payload valuecorresponding to each instruction content, different values may be usedand correspond to the technical scope of the present invention.

An ADT control packet structure of the wireless power receiving devicemay be the same as that of FIG. 47.

FIG. 48 illustrates a structure of an ADT control packet (ADT_PRxcontrol packet) of the wireless power receiving device according to anembodiment.

Referring to FIG. 48, the ADT control packet of the wireless powerreceiving device is configured with, for example, 1 byte, and a valuethereof may indicate ACK, NACK, SOD, and EOD. Table 12 represents thecorresponding relationship between a payload value of the ADT controlpacket and an instruction content thereof.

TABLE 12 Payload value Indication content ‘11111111’b ACK ‘00000000’bNACK ‘00110011’b SOD ‘11001100’b EOD

In Table 12, when the payload value is ‘11111111’b, the payload valuerepresents that the wireless power receiving device has successfullyreceived and decoded the ADT data packet transmitted by the wirelesspower transmitting device at an immediately preceding ADT (ACK). Whenthe payload value is ‘00000000’b, the payload value represents that thewireless power receiving device has not successfully received anddecoded the ADT data packet transmitted by the wireless powertransmitting device at an immediately preceding ADT (NACK). In thiscase, the wireless power transmitting device retransmits the immediatelypreceding ADT data packet at a current ADT, and in this case, the headerof the ADT data packet has a value corresponding to retransmission ofthe immediately preceding data packet (e.g., 0x1C). When the payloadvalue is ‘00110011’b, the payload value represents a request of thestart of ADT data stream (SOD). When the payload value is ‘11001100’b,the payload value represents the end of the ADT data stream (EOD).

In Table 12, the payload value and instruction content thereof are anexample, and as a payload value corresponding to each instructioncontent, different values may be used and correspond to the technicalscope of the present invention.

Hereinafter, ADT (ADT_PTx) of the wireless power transmitting devicewill be described.

FIG. 49 illustrates a structure of an ADT data packet (ADT_PTx datapacket) of the wireless power transmitting device according to anembodiment.

Referring to FIG. 49, the ADT data packet includes, for example, (n+1)bytes of payload, and each payload may correspond to any one of multipleheader types. Table 13 represents the corresponding relationship betweena header and a payload size of the ADT data packet (when n=3, maximum 4bytes).

TABLE 13 Payload Size (byte) Header A Header B 1 0x1C 0x1D 2 0x2C 0x2D 30x3C 0x3D 4 0x4C 0x4D

Referring to Table 13, when a payload of a particular byte is includedand transmitted in the ADT data packet, a header A or B may be used. Apayload size may be 1 byte to 4 bytes. The wireless power transmittingdevice and the wireless power receiving device may pursuesynchronization between each other by specifically promising a patternof a header value when transmitting a new ADT data packet and whenretransmitting an immediately preceding ADT data packet. For example, ina situation where the wireless power transmitting device transmits 1byte of payload to the ADT data packet, when transmitting a new ADT datapacket, the wireless power transmitting device may toggle a header valuefrom a header A (=0x1C) to a header B (=0x1D) or from a header B (=0x1D)to a header A (=0x1C), and when retransmitting an immediately precedingADT data packet, the wireless power transmitting device may maintain animmediately preceding header value. A situation of retransmitting theimmediately preceding ADT data packet may be when the wireless powertransmitting device receives a NACK response from the wireless powerreceiving device or when the wireless power transmitting device finds adecoding error of the wireless power receiving device.

FIG. 50 illustrates a structure of an ADT response packet (ADT_PTxresponse packet) of the wireless power transmitting device according toan embodiment.

Referring to FIG. 50, the ADT response packet of the wireless powertransmitting device is configured with, for example, 1 byte, and a valuethereof may indicate ACK, NACK, and RFA. Table 14 represents thecorresponding relationship between a payload value of the ADT responsepacket and indication content thereof.

TABLE 14 Payload value Indication content ‘11111111’b ACK ‘00000000’bNACK ‘00110011’b RFA

In Table 14, when a payload value is ‘11111111’b, the payload valuerepresents that the wireless power transmitting device has successfullyreceived and decoded an ADT data packet transmitted by the wirelesspower receiving device at an immediately preceding ADT (ACK). When thepayload value is ‘00000000’b, the payload value represents that thewireless power transmitting device has not successfully received anddecoded an ADT data packet transmitted by the wireless power receivingdevice at an immediately preceding ADT (NACK). In this case, thewireless power receiving device retransmits the immediately precedingADT data packet at a current ADT, and in this case, the header of theADT data packet has a value corresponding to retransmission of theimmediately preceding data packet (e.g., 0x1C). When the payload valueis ‘00110011’b, the payload value represents that the wireless powertransmitting device requests the wireless power receiving device toprovide a ADT transaction (RFA). In Table 14, the payload value andinstruction content thereof are an example, and as a payload valuecorresponding to each instruction content, different values may be usedand correspond to the technical scope of the present invention.

FIG. 51 illustrates a structure of an ADT response/control packet(ADT_PTx response/control packet) of the wireless power transmittingdevice according to an embodiment.

Referring to FIG. 51, the ADT response packet of the wireless powertransmitting device is configured with, for example, 1 byte, and a valuethereof may indicate ACK and RFA. Table 15 represents the correspondingrelationship between a payload value of the ADT response packet andindication content thereof.

TABLE 15 Payload value Indication content ‘11111111’b ACK ‘00110011’bRFA

In Table 15, when the payload value is ‘11111111’b, the payload valuerepresents that the wireless power transmitting device has successfullyreceived and decoded an ADT data packet transmitted by the wirelesspower receiving device at an immediately preceding ADT (ACK). When thepayload value is ‘00110011’b, the payload value represents that thewireless power transmitting device requests to transmit response data tothe wireless power receiving device (RFA). According to the presentembodiment, when the wireless power transmitting device has notsuccessfully received and decoded an ADT data packet transmitted by thewireless power receiving device at an immediately preceding ADT, thewireless power transmitting device does not transmit a separatecommunication error signal (NACK). In Table 15, the payload value andthe instruction content thereof are an example, as a payload valuecorresponding to each instruction content, different values may be usedand correspond to the technical scope of the present invention.

FIG. 52 illustrates a structure of an ADT control packet (ADT_PTxcontrol packet) of a wireless power transmitting device according to anembodiment.

Referring to FIG. 52, the ADT control packet of the wireless powertransmitting device is configured with, for example, 1 byte, and a valuethereof may indicate ACK, NACK, SOD, and EOD. Table 16 represents thecorresponding relationship between a payload value of the ADT controlpacket and instruction content thereof.

TABLE 16 Payload value Indication content ‘11111111’b ACK ‘00000000’bNACK ‘00110011’b SOD ‘11001100’b EOD

In Table 16, when a payload value is ‘11111111’b, the payload valuerepresents that the wireless power transmitting device has successfullyreceived and decoded an ADT data packet transmitted by the wirelesspower receiving device at an immediately preceding ADT (ACK). When apayload value is ‘00000000’b, the payload value represents that thewireless power transmitting device has not successfully received anddecoded an ADT data packet transmitted by the wireless power receivingdevice at an immediately preceding ADT (NACK). In this case, thewireless power receiving device retransmits an immediately preceding ADTdata packet in a current ADT, and in this case, the header of the ADTdata packet has a value corresponding to retransmission of theimmediately preceding data packet (e.g., 0x1C). When the payload valueis ‘00110011’b, the payload value represents a request of the start ofADT data stream (SOD). When the payload value is ‘11001100’b, thepayload value represents the end of the ADT data stream (EOD). In Table16, the payload value and the indication content are an example, and asa payload value corresponding to each instruction content, differentvalues may be used and correspond to the technical scope of the presentinvention.

The following description discloses embodiments of implementing anauthentication sequence based on data transport and a packet structureof the same low level as that of the above-described ADT.

2) Data Transaction Sequence of a Lower Level for Authentication (Basedon ADT)

FIG. 53 is a diagram illustrating a state machine on ADT data packetwrite according to an embodiment.

Referring to FIG. 53, the transmission side and/or the receiving sideperforms synchronization of data stream according to the rule 3, asshown in FIG. 53. That is, whenever a new ADT data packet [n] istransmitted for synchronization, a header of the ADT data packet [n] maybe toggled. The header of the ADT packet may indicate the ADT datapacket, and in this case, the header of the ADT data packet may includemultiple types of headers (e.g., two types of headers of a header A anda header B). Whenever a new ADT data packet is transmitted successfully(ACK), the header of the ADT data packet is toggled to A->B or B->A andthus synchronization of the data stream may be achieved. When thewireless power receiving device receives a NACK response from thewireless power transmitting device or when the wireless power receivingdevice finds a decoding error of the wireless power transmitting device,the wireless power receiving device retransmits an immediately precedingADT data packet, and in this case, an immediately preceding header valuemay be maintained.

2-1) Authentication of the Wireless Power Transmitting Device by theWireless Power Receiving Device (Authentication of PTx by PRx)

As an ADT-based low level authentication sequence, authentication of thewireless power transmitting device by the wireless power receivingdevice (PRx=Initiator/PTx=Responder) will be first described.

FIG. 54 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and the wireless powerreceiving device upon exchanging an ADT data packet according to anembodiment.

Referring to FIG. 54, H_A represents an A-type header, and H_Brepresents a B-type header. In the wireless power receiving device(sender), when data 1 of a higher level are transmitted to a lower leveland are transmitted to the wireless power transmitting device togetherwith the header A, a lower level of the wireless power transmittingdevice transmits data 1 to the upper level. When reception of the data 1is successful, the wireless power transmitting device transmits ACK ofthe data 1 to the wireless power receiving device. The wireless powerreceiving device transfers new data 2 from the higher level to the lowerlevel and transmits the new 2 data together with the header B to thewireless power transmitting device, and in this case, when the wirelesspower transmitting device fails in reception of the data 2, the wirelesspower transmitting device transmits NACK to the wireless power receivingdevice. Because the wireless power receiving device received NACK, thewireless power receiving device retransmits the data 2 together with animmediately preceding header B. In this way, the wireless powerreceiving device and the wireless power transmitting device may obtainsynchronization and implement simple and robust error recovery andsynchronization mechanism.

FIG. 55 illustrates a transmission sequence of a high level and a lowlevel of the wireless power transmitting device and the wireless powerreceiving device upon exchanging an ADT data packet according to anotherembodiment. Here, the wireless power receiving device is anauthentication initiator, and the wireless power transmitting device isan authentication responder. ADT data packet exchange between thewireless power receiving device and transmitting device is performedaccording to the above (1) low level authentication sequence and (2)lower level data transaction protocol.

Referring to FIG. 55, the wireless power receiving device generates Mbytes of CHALLENGE message at a high level to transfer the CHALLENGEmessage to the lower level, and the lower level loads the CHALLENGEmessage in the ADT data packet (or transport) and transmits the ADT datapacket (or transport) to the wireless power transmitting device.

The ADT data packet of the CHALLENGE message according to the low levelauthentication sequence may be transmitted over several times, and whilethe ADT data packet is transmitted over several times according to therule 2, the wireless power transmitting device transmits ACK/NACK on anADT data packet of each turn at a lower level to the wireless powerreceiving device and transfers the ADT data packet to the higher level.When transmission of the CHALLENGE message (high level viewpoint) or theADT data packet (lower level viewpoint) of the CHALLENGE message iscomplete through such a series of processes, the wireless powerreceiving device adds EOD to the end of the ADT data packet of theCHALLENGE message according to the rule 4 to notify completion oftransmission.

The wireless power receiving device inquires whether there is datastream to be transmitted by the wireless power transmitting device,which is a slave according to the rule 1. For this reason, the wirelesspower receiving device may transmit the SOD. In this case, the wirelesspower receiving device may transmit repeatedly the SOD until thewireless power transmitting device responds to the data packet or untiltime-out occurs. When the wireless power transmitting device receivesthe SOD, the wireless power transmitting device generates N bytes ofCHALLENGE_AUTH_RESPONSE at a high level to transfer theCHALLENGE_AUTH_RESPONSE to the lower level, and the lower level loadsthe CHALLENGE_AUTH_RESPONSE in the ADT data packet (or transport) andtransmits the ADT data packet (or transport) to the wireless powerreceiving device.

The ADT data packet of the CHALLENGE_AUTH_RESPONSE message may betransmitted over several times according to a low level authenticationsequence, and while the ADT data packet is transmitted over severaltimes according to the rule 2, the wireless power receiving devicetransmits ACK/NACK of the ADT data packet of each turn at a lower levelto the wireless power transmitting device and transfers the ADT datapacket to the upper level. When transmission of aCHALLENGE_AUTH_RESPONSE message (high level viewpoint) or an ADT datapacket (lower level viewpoint) of the CHALLENGE_AUTH_RESPONSE message iscompleted through such a series of process, the wireless powertransmitting device adds EOD to the end of the ADT data packet of theCHALLENGE_AUTH_RESPONSE message according to the rule 4 to notifycompletion of transmission.

FIG. 56 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and the wireless powerreceiving device upon exchanging an ADT data packet according to anotherembodiment.

The embodiment of FIG. 56 is different from the embodiment of FIG. 55 inthat addition of SOD and EOD according to the rule 4 is strictlyfollowed and a general request packet (GRP) is used instead of SOD forinquiry (or polling) according to the rule 1 upon transmitting every ADTdata packet.

FIG. 57 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to an embodiment.

Referring to FIG. 57, when bit stream (i.e. 35 bytes) for anauthentication message is prepared, the wireless power receiving devicetransmits an ADT data packet including a header (i.e. 1 byte) and apayload (i.e. 34 bytes) at a low level. Here, the authentication messagemay be, for example, a CHALLENGE message transmitted from the wirelesspower receiving device to the wireless power transmitting device.

Because the ADT data packet may be transmitted up to 16 bytes, 35 bytesof authentication message is divided and transmitted into 16 bytes of0th ADT data packet (ADT_PRx (0)), 16 bytes of first ADT data packet(ADT_PRx (1)), and 3 bytes of second ADT data packet (ADT_PRx (2)).

First, in a first line, after successfully transmitting the 0th ADT datapacket (ADT_PRx (0)), the wireless power receiving device receives ACK,but fails in transmission of the first ADT data packet (ADT_PRx (1)) andreceives NACK. Thereafter, in a second line, the wireless powerreceiving device retransmits the first ADT data packet (ADT_PRx (1)),but fails in reception of a response (ACK or NACK) thereof and transmitsNACK. Therefore, when the wireless power transmitting device responds toACK, it is determined that retransmission of the first ADT data packet(ADT_PRx (1)) was successful and thus the wireless power receivingdevice successfully transmits the remaining 3 bytes of second ADT datapacket (ADT_PRx (2)) and receives ACK. Therefore, the wireless powerreceiving device successfully transmits EOD and receives ACK, therebyending transmission of the authentication message.

FIG. 58 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 58 is different from the embodiment of FIG. 57 inthat when the wireless power receiving device divides and transmitstotal 35 bytes of authentication message into 16 bytes of 0th ADT datapacket (ADT_PRx (0)), 16 bytes of first ADT data packet (ADT_PRx (1)),and 3 bytes of second ADT data packet (ADT_PRx (2)), if the wirelesspower receiving device toggles (header A<->header B) a header of everyADT data packet according to the rules 3, but when the wireless powerreceiving device retransmits the ADT data packet, the wireless powerreceiving device performs simplified synchronization and indicatesretransmission by equally using a previously used header (header B inFIG. 58).

FIG. 59 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 59 is the same as the embodiment of FIG. 58 in thatwhen the wireless power receiving device divides and transmits total 35bytes of authentication message into 16 bytes of 0th ADT data packet(ADT_PRx (0)), 16 bytes of first ADT data packet (ADT_PRx (1)), and 3bytes of second ADT data packet (ADT_PRx (2)), the wireless powerreceiving device toggles (header A<->header B) a header of every ADTdata packet according to the rule 3, but the embodiment of FIG. 59 isdifferent from the embodiment of FIG. 58 in that the wireless powerreceiving device adds SOD when initiating transmission of the ADT datapacket.

FIG. 60 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 60 is different from the embodiment of FIG. 58 inthat when the wireless power receiving device divides and transmitstotal 35 bytes of authentication message into 16 bytes of 0th ADT datapacket (ADT_PRx (0)), 16 bytes of first ADT data packet (ADT_PRx (1)),and 3 bytes of second ADT data packet (ADT_PRx (2)), if transmission ofthe second ADT data packet (ADT_PRx (2)) is failed, the header shouldnot be toggled, but in a state in which the header is toggled,retransmission of the second ADT data packet (ADT_PRx (2)) occurs. Here,a bit pattern response may be used instead of an ADT response packet ofthe wireless power transmitting device and thus an ADT exchange time maybe reduced.

FIG. 61 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 61 describes a scenario in which when the wirelesspower receiving device divides and transmits total 35 bytes ofauthentication message into 16 bytes of 0th ADT data packet (ADT_PRx(0)), 16 bytes of first ADT data packet (ADT_PRx (1)), and 3 bytes ofsecond ADT data packet (ADT_PRx (2)), transmission of the 0th ADT datapacket (ADT_PRx (0)) and the 16 bytes of first ADT data packet (ADT_PRx(1)) is successful, but there is no response in transmission of thesecond ADT data packet (ADT_PRx (2)) and thus transmission is failed.

FIG. 62 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to an embodiment.

Referring to FIG. 62, bit stream (i.e. 99 bytes) for an authenticationresponse message is prepared. The authentication response message maybe, for example, a CHALLENGE_AUTH_RESPONSE message transmitted from thewireless power transmitting device to the wireless power receivingdevice.

When a communication protocol (i.e. FSK) of PTx->PRx direction is used,an ADT data packet may be transmitted up to 4 bytes and thus 99 bytes ofauthentication response message is divided and transmitted into 4 bytesof 0th ADT data packet (ADT_PTx (0)), 4 bytes of first ADT data packet(ADT_PTx (1)), . . . , 4 bytes of 23rd ADT data packet (ADT_PTx (23)),and 3 bytes of 24th ADT data packet (ADT_PTx (24)).

First, when the wireless power receiving device transmits SOD to thewireless power transmitting device for polling, after successfullytransmitting the 0th ADT data packet (ADT_PTx (0)), the wireless powertransmitting device receives ACK. However, the wireless powertransmitting device fails in transmission of the first ADT data packet(ADT_PTx (1)) and receives NACK. Thereafter, the wireless powertransmitting device retransmits the first data packet ADT (ADT_PTx (1)),but fails in reception of ACK thereof and transmits NACK. Therefore,when the wireless power receiving device responds to ACK, it isdetermined that retransmission of the first ADT data packet (ADT_PTx(1)) was successful and thus the wireless power transmitting devicetransmits the second ADT data packet (ADT_PTx (2)). After repeating anADT packet transmission sequence, the wireless power transmitting devicesuccessfully transmits the last remaining 3 bytes of 24 ADT data packet(ADT_PTx (24)) and receives ACK. Therefore, the wireless powertransmitting device successfully transmits EOD and receives ACK, therebyending transmission of the authentication response message.

FIG. 63 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 63 is different from the embodiment of FIG. 62 inthat when the wireless power transmitting device divides and transmitstotal 99 bytes of authentication message into 4 bytes of 0th ADT datapacket (ADT_PRx (0)), 4 bytes of first ADT data packet (ADT_PRx (1)), .. . , 4 bytes of 23rd ADT data packet (ADT_PTx (23)), and 3 bytes of 24ADT data packet (ADT_PTx (24)), the wireless power transmitting devicetoggles (header A<->header B) a header of every ADT data packetaccording to the rule 3, but when the wireless power transmitting deviceperforms retransmission of the first ADT data packet, the wireless powertransmitting device equally uses a previously used header (header B inFIG. 62), thereby performing simplified synchronization and indicatingretransmission.

FIG. 64 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 64 is the same as the embodiment of FIG. 63 in thatwhen the wireless power transmitting device divides and transmits total99 bytes of authentication message into 4 bytes of 0th ADT data packet(ADT_PRx (0)), 4 bytes of first ADT data packet (ADT_PRx (1)), . . . , 4bytes of 23rd ADT data packet (ADT_PTx (23)), and 3 bytes of 24 ADT datapacket (ADT_PTx (24)), the wireless power receiving device toggles(header A<->header B) a header of every ADT data packet according to therule 3, but the embodiment of FIG. 64 is different from the embodimentof FIG. 63 in that the wireless power receiving device uses a GRP inpolling the wireless power transmitting device and the wireless powertransmitting device responds to SOD and thus transmission of the ADTdata packet is started.

FIG. 65 illustrates an exchange sequence of an ADT data packet of theauthentication response message according to another embodiment. Theembodiment of FIG. 65 is different from the embodiment of FIG. 64 inthat when the wireless power transmitting device divides and transmitstotal 99 bytes of authentication message into 4 bytes of 0th ADT datapacket (ADT_PRx (0)), 4 bytes of first ADT data packet (ADT_PRx (1)), .. . , 4 bytes of 23rd ADT data packet (ADT_PTx (23)), and 3 bytes of 24ADT data packet (ADT_PTx (24)), if the wireless power receiving devicefails in transmission of the first ADT data packet (ADT_PRx (1)), theheader should not be toggled, but in a state in which the header istoggled, retransmission of the first data packet ADT (ADT_PTx (1))occurs.

FIG. 66 illustrates an exchange sequence of an ADT data packet of theauthentication response message according to another embodiment. Theembodiment of FIG. 66 describes a scenario in which when the wirelesspower transmitting device divides and transmits total 99 bytes ofauthentication message into 4 bytes of 0th ADT data packet (ADT_PRx(0)), 4 bytes of first ADT data packet (ADT_PRx (1)), . . . , 4 bytes of23rd ADT data packet (ADT_PTx (23)), and 3 bytes of 24 ADT data packet(ADT_PTx (24)), transmission of the 0th ADT data packet (ADT_PRx (0)) issuccessful, but there is no response to the first ADT data packet(ADT_PRx (1)) and thus transmission is failed.

2-2) Authentication of the Wireless Power Receiving Device by theWireless Power Transmitting Device (Authentication of PRx by PTx)

As an ADT-based low level authentication sequence, authentication of thewireless power receiving device by the wireless power transmittingdevice (PTx=Initiator/PRx=Responder) will be described. When followingthe rule 1, the wireless power transmitting device is a slave and thuswhen it is determined that the wireless power transmitting deviceoperates as an authentication initiator based on an AI bit in acapability packet of the wireless power transmitting device, thewireless power receiving device should provide ADT to the wireless powertransmitting device.

FIG. 67 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and the wireless powerreceiving device upon exchanging an ADT data packet according to anembodiment. Here, the wireless power transmitting device is anauthentication initiator, and the wireless power receiving device is anauthentication responder. ADT data packet exchange between the wirelesspower receiving device and transmitting device is performed according tothe above (1) low level authentication sequence and (2) lower level datatransaction protocol.

Referring to FIG. 67, the wireless power transmitting device is polledby SOD provided by the wireless power receiving device to generate Mbytes of CHALLENGE message at a high level and to transfer the CHALLENGEmessage to a low level, and the low level loads the CHALLENGE message inthe ADT data packet (or transport) and transmits the ADT data packet (ortransport) to the wireless power receiving device. In this case, thewireless power receiving device may transmit repeatedly SOD until thewireless power transmitting device responds to the ADT data packet oruntil time-out occur.

ADT data packets of the CHALLENGE message according to the low levelauthentication sequence may be transmitted over several times, and whilethe ADT data packet is transmitted over several times according to therule 2, the wireless power receiving device transmits ACK/NACK of an ADTdata packet of each turn at a lower level to the wireless powertransmitting device and transfers the ADT data packet to a higher level.When transmission of the CHALLENGE message (high level viewpoint) or theADT data packet (lower level viewpoint) of the CHALLENGE message iscomplete through such a series of processes, the wireless powertransmitting device adds EOD to the end of the ADT data packet on theCHALLENGE message according to the rule 4 to notify completion oftransmission.

Because the wireless power receiving device operates as a masteraccording to the rule 1, the wireless power receiving device generates Nbytes of CHALLENGE message at a higher level without separate poolingfor a CHALLENGE_AUTH_RESPONSE message to be transmitted and transfersthe CHALLENGE message to the lower level, and the lower level loads theCHALLENGE message in the ADT data packet (or transport) and transmitsthe ADT data packet (or transport) to the wireless power transmittingdevice.

An ADT data packet of the CHALLENGE_AUTH_RESPONSE message according tothe low level authentication sequence may be transmitted over severaltimes, and while the ADT data packet is transmitted over several timesaccording to the rule 2, the wireless power transmitting devicetransmits ACK/NACK of an ADT data packet of each turn at a lower levelto the wireless power receiving device and transfers the ADT data packetto a higher level. When transmission of the CHALLENGE_AUTH_RESPONSEmessage (high level viewpoint) or the ADT data packet (lower levelviewpoint) of the CHALLENGE_AUTH_RESPONSE message is complete throughsuch a series of processes, the wireless power receiving device adds EODto the end of the ADT data packet of the CHALLENGE_AUTH_RESPONSE messageaccording to the rule 4 to notify completion of transmission.

FIG. 68 illustrates a transmission sequence of a high level and a lowlevel of a wireless power transmitting device and the wireless powerreceiving device upon exchanging an ADT data packet according to anotherembodiment.

The embodiment of FIG. 68 strictly follows addition of SOD and EODaccording to the rule 4 when transmitting every ADT data packet, but isdifferent from the embodiment of FIG. 67 in that the wireless powerreceiving device uses a general request packet (GRP) instead of SOD forinquiry (or polling) according to the rule 1.

FIG. 69 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to an embodiment.

Referring to FIG. 69, when bit stream (i.e. 35 bytes) for anauthentication request message is prepared, the wireless powertransmitting device stands by to transmit an ADT data packet including aheader (i.e. 1 byte) and a payload (i.e. 34 byte) in a lower level.Here, the authentication request message may be, for example, aCHALLENGE message.

In this case, the wireless power receiving device performs a pollingoperation for determining whether there are data to be transmitted fromthe wireless power transmitting device, and for this, the wireless powerreceiving device transmits repeatedly SOD until the wireless powertransmitting device responds or until time-out occurs.

When the wireless power transmitting device receives the opportunity totransmit an authentication request message by the SOD, the wirelesspower transmitting device initiates transmission of an ADT data packet.When using a communication protocol (FSK) of PTx->PRx direction, the ADTdata packet may be transmitted up to 4 bytes and thus 35 bytes ofauthentication message is divided and transmitted into 4 bytes of 0thADT data packet (ADT_PRx (0)), 4 bytes of ADT first data packet (ADT_PTx(1)), . . . , 4 bytes of 7th ADT data packet (ADT_PTx (7)), and 3 bytesof 8th ADT data packet (ADT_PTx (8)).

First, after successfully transmitting the 0th ADT data packet (ADT_PTx(0)), the wireless power transmitting device receives ACK, but thewireless power transmitting device fails in transmission of the firstADT data packet (ADT_PTx (1)) and receives NACK. Thereafter, thewireless power transmitting device retransmits the first data packet ADT(ADT_PTx (1)), but the wireless power transmitting device fails inreception of an ACK response thereof and transmits NACK. When thewireless power receiving device responds to ACK, it is determined thatretransmission of the first ADT data packet (ADT_PTx (1)) was successfuland thus the wireless power transmitting device transmits a next secondADT data packet (ADT_PTx (2)). When transmission of all ADT data packetsup to the last ADT data packet is completed, the wireless powertransmitting device successfully transmits EOD and receives ACK, therebyending transmission of the authentication request message.

FIG. 70 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 70 is different from the embodiment of FIG. 69 inthat when the wireless power transmitting device divides and transmitstotal 35 bytes of authentication request message into 4 bytes of 0th ADTdata packet (ADT_PTx (0)), 4 bytes of first ADT data packet (ADT_PTx(1)) . . . . , 4 bytes of 7th ADT data packet (ADT_PTx (7)), and 3 bytesof 8th ADT data packet (ADT_PTx (8)), the wireless power transmittingdevice toggles (header A<->header B) a header of every ADT data packetaccording to the rule 3, but when the wireless power transmitting deviceperforms retransmission of the ADT data packet, the wireless powertransmitting device equally uses a previously used header (header B inFIG. 58), thereby performing simplified synchronization and indicatingretransmission.

FIG. 71 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 71 is the same as the embodiment of FIG. 70 in thatwhen the wireless power transmitting device divides and transmits total35 bytes of authentication request message into 4 bytes of 0th ADT datapacket (ADT_PTx (0)), 4 bytes of first ADT data packet (ADT_PTx (1)), .. . , 4 bytes of 7th ADT data packet (ADT_PTx (7)), and 3 bytes of 8thADT data packet (ADT_PTx (8)), the wireless power transmitting devicetoggles (header A<->header B) a header of every ADT packet dataaccording to the rule 3, but the embodiment of FIG. 71 is different fromthe embodiment of FIG. 70 in that the wireless power receiving deviceuses a GRP in polling the wireless power transmitting device and thewireless power transmitting device responds to SOD and thus transmissionof ADT packet data is started.

FIG. 72 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 72 is different from the embodiment of FIG. 71 inthat when the wireless power transmitting device divides and transmitstotal 35 bytes of authentication request message into 4 bytes of 0th ADTdata packet (ADT_PTx (0)), 4 bytes of first ADT data packet (ADT_PTx(1)), . . . , 4 bytes of 7th ADT data packet (ADT_PTx (7)), and 3 bytesof 8th ADT data packet (ADT_PTx (8)), the wireless power transmittingdevice receives a RPP and transmits an RFA bit pattern in a mode 0 toobtain a transmission opportunity of the ADT data packet. Further, theembodiment of FIG. 72 is different from the embodiment of FIG. 71 inthat when transmission of the first ADT data packet (ADT_PTx (1)) isfailed, the header should not be toggled, but in a state in which theheader is toggled, retransmission of the first ADT data packet (ADT_PTx(1)) occurs.

FIG. 73 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 73 describes a scenario in which when the wirelesspower transmitting device divides and transmits total 35 bytes ofauthentication request message into 4 bytes of 0th ADT data packet(ADT_PTx (0)), 4 bytes of first ADT data packet (ADT_PTx (1)), . . . , 4bytes of 7th ADT data packet (ADT_PTx (7)), and 3 bytes of 8th ADT datapacket (ADT_PTx (8)), transmission of the 0th ADT data packet (ADT_PTx(0)) is successful, but in which there is no response to the first ADTdata packet (ADT_PTx (1)) and thus transmission is failed.

FIG. 74 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to an embodiment.

Referring to FIG. 74, when bit stream (i.e. 99 bytes) for anauthentication response message is prepared, the wireless powerreceiving device transmits an ADT data packet including a header (i.e. 1byte) and a payload (i.e. 34 bytes) at a low level. Here, theauthentication response message may be, for example, aCHALLENGE_AUTH_RESPONSE message.

After successfully transmitting the 0th ADT data packet (ADT_PRx (0)),the wireless power receiving device receives ACK. However, the wirelesspower receiving device fails in transmission of the first ADT datapacket (ADT_PRx (1)) and receives NACK. Thereafter, the wireless powerreceiving device retransmits the first data packet ADT (ADT_PRx (1)),but fails in receiving ACK thereof and transmits NACK. When the wirelesspower transmitting device responds to ACK, it is determined thatretransmission of the first ADT data packet (ADT_PRx (1)) was successfuland thus the wireless power receiving device transmits the second ADTdata packet (ADT_PRx (2)). After repeating such an ADT packettransmission sequence, the wireless power transmitting devicesuccessfully transmits the last remaining ADT data packet (ADT_PRx) andthen receives ACK. Therefore, the wireless power receiving devicesuccessfully transmits EOD and receives ACK, thereby ending transmissionof the authentication response message.

FIG. 75 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 75 is different from the embodiment of FIG. 74 inthat when the wireless power receiving device divides and transmitstotal 99 bytes of authentication response message into 16 bytes of 0thADT data packet (ADT_PRx (0)), 16 bytes of first ADT data packet(ADT_PRx (1)), . . . , 16 bytes of 5th ADT data packet (ADT_PRx (5)),and 3 bytes of 6th ADT data packet (ADT_PRx (6)), the wireless powerreceiving device toggles (header A<->header B) a header of every ADTdata packet according to rule 3, but when retransmitting the first ADTdata packet, the wireless power receiving device equally uses apreviously used header (header B in FIG. 75) and thus simplifiedsynchronization is performed and retransmission is indicated.

FIG. 76 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 76 is different from the embodiment of FIG. 75 inthat when the wireless power receiving device divides and transmitstotal 99 bytes of authentication response message into 16 bytes of 0thADT data packet (ADT_PRx (0)), 16 bytes of first ADT data packet(ADT_PRx (1)), . . . , 16 bytes of 5th ADT data packet (ADT_PRx (5)),and 3 bytes of 6th ADT data packet (ADT_PRx (6)), if transmission of thefirst ADT data packet (ADT_PRx (1)) is failed, a header should not betoggled, but in a state in which the header is toggled, retransmissionof the first data packet ADT (ADT_PRx (1)) occurs.

FIG. 77 illustrates an exchange sequence of an ADT data packet of anauthentication request message according to another embodiment. Theembodiment of FIG. 77 describes a scenario in which when the wirelesspower receiving device divides and transmits total 99 bytes ofauthentication response message into 16 bytes of 0th ADT data packet(ADT_PRx (0)), 16 bytes of first ADT data packet (ADT_PRx (1)), . . . ,16 bytes of fifth ADT data packet (ADT_PRx (5)), and 3 bytes of sixthADT data packet (ADT_PRx (6)), transmission of the 0th ADT data packet(ADT_PRx (0)) is successful, but in which there is no response totransmission of the first ADT data packet (ADT_PRx (1)) and thustransmission is failed.

2-3) Concurrent Authentication Between the Wireless Power TransmittingDevice and the Wireless Power Receiving Device (ConcurrentAuthentication Between PTx and PRx)

Both the wireless power transmitting device and the wireless powerreceiving device may simultaneously perform operations as anauthentication initiator.

As an example, the wireless power transmitting device may transmit ADTincluding an authentication related packet instead of ADT including ACKfor a packet received from the wireless power receiving device. In thiscase, by receiving ADT including the authentication related packet, itis regarded that the wireless power receiving device has implicitlyreceived ACK and may perform the following operation. That is, when thewireless power transmitting device transmits ADT including data(authentication related packet), even if the wireless power receivingdevice receives data ADT instead of ACK, the wireless power receivingdevice may determine that ADT data transmitted immediately before to thewireless power transmitting device were successfully transmitted.However, when a communication error occurs in ADT data receivedimmediately before from the wireless power receiving device, thewireless power transmitting device may transmit NACK. ADT including theauthentication related packet may further include ACK.

As another example, the wireless power receiving device may transmit ADTincluding the authentication related packet instead of ADT including ACKfor the packet received from the wireless power transmitting device. Inthis case, by receiving ADT including the authentication related packet,it is regarded that the wireless power transmitting device hasimplicitly received ACK and may perform the following operation. Thatis, when the wireless power receiving device transmits ADT includingdata (authentication related packet), even if the wireless powertransmitting device receives data ADT instead of ACK, the wireless powerreceiving device may determine that ADT data transmitted immediatelybefore to the wireless power transmitting device was successfullytransmitted. ADT including the authentication related packet may furtherinclude ACK.

2-4) Communication Initiation Protocol by the Wireless PowerTransmitting Device

While the wireless power transmitting device operates as a slave basedon the rule 1, by performing regular polling, the wireless powerreceiving device may provide an opportunity of communication (PTxinitiated communication) initiated by the wireless power transmittingdevice. In this case, communication initiation of the wireless powertransmitting device has high dependency in the wireless power receivingdevice. By regularly polling the wireless power transmitting device, thewireless power receiving device may determine whether the wireless powertransmitting device has a packet to transmit. In this case, a GRP ofFIG. 78 may be used. Referring to FIG. 78, for example, by setting ageneral request packet to “0xFF”, “00”, or “FF”, the wireless powerreceiving device may perform polling. When the wireless powertransmitting device receives the GRP set to “0xFF”, “00”, or “FF”, thewireless power transmitting device is in a state that may transmit anytype of packet to transmit.

As another method for further ensuring a communication opportunityinitiated by the wireless power transmitting device, the wireless powertransmitting device may transmit a request for communication (RFC) bitpattern in response to an RPP (except for a mode ‘100’b) of the wirelesspower receiving device. When the wireless power receiving devicereceives the RFC response, the wireless power receiving device polls thewireless power transmitting device using a GRP at timing appropriatethereto. The wireless power receiving device may not accurately know atime point in which a value of target power managed by the wirelesspower transmitting device changes and may relatively well guarantee adesired communication initiation time of the wireless power transmittingdevice through the RFC response of the wireless power transmittingdevice.

In particular, polling by the RFC response may be used for powermanagement (PTx-initiated power management) initiated by the wirelesspower transmitting device. By power management initiated by the wirelesspower transmitting device, the wireless power transmitting device maychange (increase or decrease) target power in consideration of currentperipheral charging conditions.

FIG. 79 illustrates a transmission sequence of power managementinitiated by a wireless power transmitting device according to anembodiment.

Referring to FIG. 79, the wireless power transmitting device transmitsalert including an RFC response (bit pattern) to the wireless powerreceiving device in response to the RPP (mode 0) of the wireless powerreceiving device. The wireless power receiving device transmits a GRP inwhich a request value is set to “0xFF” to the wireless powertransmitting device. Thereafter, the wireless power transmitting devicetransmits a target power packet to the wireless power receiving device.The wireless power receiving device may control an operation modeaccording to the changed target power.

6. Application Related to Certification Procedure

An authentication function may be set to On/Off by the user. Forexample, a smart phone may display activation/deactivation of anauthentication function through an application to the user and receivean input of selection information about activation (ON) or deactivation(OFF) from the user to activate or deactivate the authenticationfunction.

Wireless power transmitting and receiving devices may provide a veryconvenient user experience and interface (UX/UI). That is, a smartwireless charging service may be provided. The smart wireless chargingservice may be implemented based on UX/UI of the smart phone includingthe wireless power transmitting device. For such an application, aninterface between a processor of the smart phone and the wirelesscharging receiver device allows two-way communication of “drop and play”between the wireless power transmitting device and receiving device.

As an example, the user may experience a smart wireless charging serviceat a hotel. When the user enters a hotel room and puts the smart phoneon a wireless charger in the room, the wireless charger transmitswireless power to the smart phone, and the smart phone receives wirelesspower. In this process, the wireless charger transmits information on asmart wireless charging service to the smart phone. When the smart phonedetects that the smart phone is positioned on the wireless charger, whenthe smart phone detects reception of wireless power, or when the smartphone receives information on a smart wireless charging service from thewireless charger, the smart phone enters a state that inquires opt-in ofan additional feature to the user. For this purpose, the smart phone maydisplay a message on a screen in a manner that includes or does notinclude an alarm sound. An example of the message may include phrasessuch as “Welcome to ### hotel. Select “Yes” to activate smart chargingfunctions: Yes No Thanks.” The smart phone receives the user's inputthat selects Yes or No Thanks and performs a next procedure selected bythe user. When Yes is selected, the smart phone transmits theinformation to the wireless charger. The smart phone and the wirelesscharger perform together a smart charging function.

The smart wireless charging service may also include reception of WiFicredentials auto-filled. For example, the wireless charger transmitsWiFi credentials to the smart phone, and the smart phone executes anappropriate app to automatically input the WiFi credentials receivedfrom the wireless charger.

The smart wireless charging service may also include execution of ahotel application that provides a hotel promotion or acquisition ofremote check-in/check-out and contact information.

As another example, the user may experience a smart wireless chargingservice in a vehicle. When the user boards a vehicle and puts the smartphone on the wireless charger, the wireless charger transmits wirelesspower to the smart phone, and the smart phone receives wireless power.In this process, the wireless charger transmits information on the smartwireless charging service to the smart phone. When the smart phonedetects that the smart phone is positioned on the wireless charger,detects reception of wireless power, or receives information on thesmart wireless charging service from the wireless charger, the smartphone enters into a state that inquires identity to the user.

In this state, the smart phone is automatically connected to the vehiclethrough WiFi and/or Bluetooth. The smart phone may display a message onthe screen in a manner that includes or does not include an alarm sound.An example of the message may include phrases such as “Welcome to usercar. Select “Yes” to synch device with in-car controls: Yes No Thanks.”The smart phone receives the user's input that selects Yes or No Thanksand performs a next procedure selected by the user. When Yes isselected, the smart phone transmits the information to the wirelesscharger. The smart phone and the wireless charger may driveapplication/display software within the vehicle to perform the softwaretogether with a smart control function within the vehicle. Users mayenjoy favorite music and determine a regular map location.Application/display software within the vehicle may include a capabilitythat provides synchronization access for passers.

As another example, the user may experience smart wireless charging in ahome. When the user enters into the room and puts the smart phone on thewireless charger in the room, the wireless charger transmits wirelesspower to the smart phone, and the smart phone receives wireless power.In this process, the wireless charger transmits information on the smartwireless charging service to the smart phone. When the smart phonedetects that the smart phone is positioned on the wireless charger,detects reception of wireless power, or receives information on thesmart wireless charging service from the wireless charger, the smartphone enters to a state that inquires opt-in to an additional feature tothe user. For this purpose, the smart phone may display a message on ascreen in a manner that includes or does not include an alarm sound. Anexample of the message may include phrases such as “Hi xxx, Would youlike to activate night mode and secure the building?: Yes No Thanks.”The smart phone receives the user's input that selects Yes or No Thanksand performs a next procedure selected by the user. When Yes isselected, the smart phone transmits the information to the wirelesscharger. The smart phone and the wireless charger may recognize at leasta user pattern and may recommend to lock doors and windows or to turnoff lights or to set an alarm to the user.

In a wireless power transmitting method and device or receiving deviceand method according to an embodiment of the present invention, becauseall components or steps are not essential, the wireless powertransmitting device and method or receiving device and method may beperformed by including some or all of the above-described components orsteps. Further, embodiments of the wireless power transmitting deviceand method or receiving device and method may be performed incombination. Further, it is not necessary that the above components orsteps should be performed in the described order, and a step describedlater may be performed prior to a step described earlier.

The foregoing description is merely illustrative of the technical ideaof the present invention, and various changes and modifications may bemade by those skilled in the art without departing from the essentialcharacteristics of the present invention. Therefore, the foregoingembodiments of the present invention can be implemented separately or incombination.

Therefore, the embodiments disclosed in the present invention areintended to illustrate rather than to limit the scope of the presentinvention, and the scope of the technical idea of the present inventionis not limited by these embodiments. The scope of protection of thepresent invention should be construed according to the following claims,and all technical ideas within the scope of equivalents to claims shouldbe construed as falling within the scope of the present invention.

What is claimed is:
 1. A wireless power transmitter comprising: a powerconversion unit configured to transfer wireless power to a wirelesspower receiver by forming magnetic coupling with the wireless powerreceiver; and a communication/control unit configured to communicatewith the wireless power receiver to control transmission of the wirelesspower and to perform transmission or reception of data, wherein thecommunication/control unit is configured to: receive, from the wirelesspower receiver after a configuration phase, a received power packet(RPP) which indicates a value of the wireless power received by thewireless power receiver; transmit, to the wireless power receiver, a bitpattern which requests communication initiated by the wireless powertransmitter in response to the RPP when the communication/control unithas data to be sent to the wireless power receiver; and receive a packetfor polling the data to be sent from the wireless power receiver inresponse to the bit pattern.
 2. The wireless power transmitter of claim1, wherein the data to be sent comprises power related information forincreasing or decreasing a level of the wireless power.
 3. The wirelesspower transmitter of claim 2, wherein the RPP indicates that thewireless power receiver is in Mode
 0. 4. The wireless power transmitterof claim 1, wherein when the RPP indicates a mode other than Mode 4, thecommunication/control unit is configured to transmit the bit pattern. 5.The wireless power transmitter of claim 1, wherein the bit pattern andthe polling packet are 8 bits respectively.
 6. A power control methodperformed by a wireless power transmitter, the method comprising:transferring wireless power to a wireless power receiver by formingmagnetic coupling with the wireless power receiver; and communicatingwith the wireless power receiver to control transmission of the wirelesspower and to perform transmission or reception of data, wherein theperforming of the transmission or reception of the data comprises:receiving, from the wireless power receiver after a configuration phase,a received power packet (RPP) which indicates a value of the wirelesspower received by the wireless power receiver; transmitting, to thewireless power receiver, a bit pattern which requests communicationinitiated by the wireless power transmitter in response to the RPP whenthe wireless power transmitter has data to be sent to the wireless powerreceiver; and receiving a packet for polling the data to be sent fromthe wireless power receiver in response to the bit pattern.
 7. Themethod of claim 6, wherein the data to be sent comprises power relatedinformation for increasing or decreasing a level of the wireless power.8. The method of claim 6, wherein the RPP indicates that the wirelesspower receiver is in Mode
 0. 9. The method of claim 6, wherein when theRPP indicates a mode other than Mode 4, the communication/control unittransmits the bit pattern.
 10. The method of claim 6, wherein the bitpattern and the polling packet are 8 bits respectively.
 11. A wirelesspower receiver comprising: a power pickup unit configured to receivewireless power from a wireless power transmitter by forming magneticcoupling with the wireless power transmitter; and acommunication/control unit configured to communicate with the wirelesspower transmitter to control transmission of the wireless power and toperform transmission or reception of data, wherein thecommunication/control unit is configured to: transmit, to the wirelesspower transmitter after a configuration phase, a received power packet(RPP) which indicates a value of the wireless power received by thewireless power receiver; receive, from the wireless power transmitter, abit pattern which requests communication initiated by the wireless powertransmitter in response to the RPP when the wireless power transmitterhas data to be sent to the wireless power receiver; and transmit apacket for polling the data to be sent to the wireless power transmitterin response to the bit pattern.
 12. The wireless power receiver of claim11, wherein the data to be sent comprises power related information forincreasing or decreasing a level of the wireless power.
 13. The wirelesspower receiver of claim 12, wherein the RPP indicates that the wirelesspower receiver is in Mode
 0. 14. The wireless power receiver of claim11, wherein when the RPP indicates a mode other than Mode 4, thecommunication/control unit is configured to transmit the bit pattern.15. The wireless power receiver of claim 11, wherein the bit pattern andthe polling packet are 8 bits respectively.